Breeding and genetics
Research Article
Invited review: Bioinformatic methods to discover the likely causal variant of a new autosomal recessive genetic condition using genome-wide data
- G. E. Pollott
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- Published online by Cambridge University Press:
- 10 August 2018, pp. 2221-2234
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In animals, new autosomal recessive genetic diseases (ARGD) arise all the time due to the regular, random mutations that occur during meiosis. In order to reduce the effect of any damaging new variant, it is necessary to find its cause. To evaluate the best way of doing this, 34 papers which found the exact location of a new genetic disease in livestock were reviewed and found to require at least two stages. In the initial stage the commonly used χ2 method, applied in a case-control association analysis with single nucleotide polymorphism (SNP)-chip data, was found to have limitations and was almost always used in conjunction with a second method to locate the target region on the genome containing the variant. The commonly used methods had their drawbacks; so a new method was devised based on long runs of homozygosity, a common feature of new ARGD. This ‘autozygosity by difference’ method was found to be as good as, or better than, all the reviewed methods tested based on its ability to unambiguously find the shortest known target region in an already analysed data set. Mean target region length was found to be 4.6 megabases in the published reports. Success did not depend on the size of commercial SNP-chip used, and studies with as few as three cases and four controls were large enough to find the target region. The final stage relied on either sequencing the candidate genes found in the target region or using whole genome sequencing (WGS) on a small number of cases. Sometimes this latter method was used in conjunction with WGS on a number of control animals or resources such as the 1000 bull genomes data. Calculations showed that, in cattle, less than 15 animals would be needed in order to locate the new variant when using WGS data. This could be any combination of cases plus parents or other unrelated animals in the breed. Using WGS data, it would be necessary to search the three billion bases of the cattle genome for base positions which were homozygous for the same allele in all cases and heterozygous for that allele in parents, or not containing that homozygote in unrelated controls. This site could be confirmed on other healthy animals using much cheaper methods, and then a genetic test could be devised for that variant in order to screen the whole population and to devise a breeding programme to eliminate the disorder from the population.
Genotype imputation from various low-density SNP panels and its impact on accuracy of genomic breeding values in pigs
- D. A. Grossi, L. F. Brito, M. Jafarikia, F. S. Schenkel, Z. Feng
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- Published online by Cambridge University Press:
- 30 April 2018, pp. 2235-2245
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The uptake of genomic selection (GS) by the swine industry is still limited by the costs of genotyping. A feasible alternative to overcome this challenge is to genotype animals using an affordable low-density (LD) single nucleotide polymorphism (SNP) chip panel followed by accurate imputation to a high-density panel. Therefore, the main objective of this study was to screen incremental densities of LD panels in order to systematically identify one that balances the tradeoffs among imputation accuracy, prediction accuracy of genomic estimated breeding values (GEBVs), and genotype density (directly associated with genotyping costs). Genotypes using the Illumina Porcine60K BeadChip were available for 1378 Duroc (DU), 2361 Landrace (LA) and 3192 Yorkshire (YO) pigs. In addition, pseudo-phenotypes (de-regressed estimated breeding values) for five economically important traits were provided for the analysis. The reference population for genotyping imputation consisted of 931 DU, 1631 LA and 2103 YO animals and the remainder individuals were included in the validation population of each breed. A LD panel of 3000 evenly spaced SNPs (LD3K) yielded high imputation accuracy rates: 93.78% (DU), 97.07% (LA) and 97.00% (YO) and high correlations (>0.97) between the predicted GEBVs using the actual 60 K SNP genotypes and the imputed 60 K SNP genotypes for all traits and breeds. The imputation accuracy was influenced by the reference population size as well as the amount of parental genotype information available in the reference population. However, parental genotype information became less important when the LD panel had at least 3000 SNPs. The correlation of the GEBVs directly increased with an increase in imputation accuracy. When genotype information for both parents was available, a panel of 300 SNPs (imputed to 60 K) yielded GEBV predictions highly correlated (⩾0.90) with genomic predictions obtained based on the true 60 K panel, for all traits and breeds. For a small reference population size with no parents on reference population, it is recommended the use of a panel at least as dense as the LD3K and, when there are two parents in the reference population, a panel as small as the LD300 might be a feasible option. These findings are of great importance for the development of LD panels for swine in order to reduce genotyping costs, increase the uptake of GS and, therefore, optimize the profitability of the swine industry.
Pedigree analysis and inbreeding effects over morphological traits in Campolina horse population
- F. O. Bussiman, B. C. Perez, R. V. Ventura, M. G. C. D. Peixoto, R. A. Curi, J. C. C. Balieiro
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- Published online by Cambridge University Press:
- 22 February 2018, pp. 2246-2255
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Genetic improvement, without control of inbreeding, can go to loss of genetic variability, reducing the potential for genetic gains in the domestic populations. The aim of this study was to analyze the population structure and the inbreeding depression in Campolina horses. Phenotype information from 43 465 individuals was analyzed, data provided by the Campolina Breeders Association. A pedigree file containing 107 951 horses was used to connected the phenotyped individuals. The inbreeding coefficient was performed by use of the diagonal of the relationship matrix and the genealogical parameters were computed using proper softwares. The effective population size was estimated based on the rate of inbreeding and census information, and the stratification of the population was verified by the average relationship coefficient between animals born in different regions of Brazil. The effects of inbreeding on morphological traits were made by the use of inbreeding coefficient as a covariate in the model of random regression. The inbreeding coefficient increased from 1990 on, impacting effective population size and, consequently, shrinking genetic variability. The paternal inbreeding was greater than maternal, which may be attributed to the preference for inbred animals in reproduction. The average genetic relationship coefficient of animals born in different states was lower than individuals born within the same state. The increase in the inbreeding coefficient was negatively associated with all studied traits, showing the importance to avoid genetic losses in the long term. Although results do not indicate a severe narrowing of the population until the present date, the average relationship coefficient shows signs of increase, which could cause a drastic reduction in genetic variability if inbred mating is not successfully controlled in the Campolina horse population.
Nutrition
Research Article
Effects of in ovo feeding of l-arginine on breast muscle growth and protein deposition in post-hatch broilers
- L. L. Yu, T. Gao, M. M. Zhao, P. A. Lv, L. Zhang, J. L. Li, Y. Jiang, F. Gao, G. H. Zhou
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- 26 February 2018, pp. 2256-2263
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In ovo feeding (IOF) of l-arginine (Arg) can affect growth performance of broilers, but the response of IOF of Arg on breast muscle growth is unclear, and the mechanism involved in protein deposition remains unknown. Hense, this experiment was conducted to evaluate the effects of IOF of Arg on breast muscle growth and protein-deposited signalling in post-hatch broilers. A total of 720 fertile eggs were collected from 34-week-old Arbor Acres breeder hens and distributed to three treatments: (1) non-injected control group; (2) 7.5 g/l (w/v) NaCl diluent-injected control group; (3) 0.6 mg Arg/egg solution-injected group. At 17.5 days of incubation, fertile eggs were injected 0.6 ml solutions into the amnion of the injected groups. Upon hatching, 80 male chicks were randomly assigned to eight replicates of 10 birds each and fed ad libitum for 21 days. The results indicated that IOF of Arg increased relative breast muscle weight compared with those of control groups at hatch, 3-, 7- and 21-day post-hatch (P<0.05). In the Arg-injected group, the plasma total protein and albumen concentrations were higher at 7- and 21-day post-hatch than those of control groups (P<0.05). The alanine aminotransferase activity in Arg group was higher at hatch than that of control groups (P<0.05). The levels of triiodothyronine at four time points and thyroxine hormones at hatch, 7- and 21-day post-hatch in Arg group were higher than those of control groups (P<0.05). In addition, IOF of Arg increased the amino acid concentrations of breast muscle at hatch, 7- and 21-day post-hatch (P<0.05). In ovo feeding of Arg also enhanced mammalian target of rapamycin, ribosomal protein S6 kinase-1 and eIF4E-bindingprotein-1 messenger RNA expression levels at hatch compared with those of control groups (P<0.05). It was concluded that IOF of Arg treatment improved breast muscle growth, which might be associated with the enhancement of protein deposition.
Effects of oral supplementation with Spirulina and Chlorella on growth and digestive health in piglets around weaning
- H. Furbeyre, J. van Milgen, T. Mener, M. Gloaguen, E. Labussière
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- 15 February 2018, pp. 2264-2273
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Weaning of piglets is associated with important changes in gut structure and function resulting from stressful events such as separation from the sow, moving to a new facility and dietary transition from a liquid to a solid feed. This may result in post-weaning diarrhoea and a decrease in feed intake and growth. In humans, the cyanobacterium Spirulina platensis (SP) and the freshwater microalga Chlorella vulgaris (CV) are known for their beneficial health effects. This study aimed to determine the effects of early oral administration of Spirulina and Chlorella in piglets on mucosal architecture and cytokine expression in the intestine around weaning, and consequences on growth performance and diarrhoea incidence. The experiment was conducted on 108 suckling piglets of 14 days of age (initial BW=4.9±0.7 kg) and weaned at 28 days of age (day 0). Animals received orally 385 mg/kg BW per day of SP or CV, or water (negative control (NC)) during 4 weeks from day −14 to day 14 and their growth performance was measured daily. After weaning, growth, feed intake and diarrhoea incidence were measured daily. Intestinal morphology and functionality were assessed at day −1, day 2, and day 14. During the suckling period, average daily gain (ADG) in SP piglets was higher, resulting in a higher weaning BW compared to NC and CV piglets (P<0.05). No significant difference between treatments was observed for ADG, average daily feed intake, and gain to feed (G : F) ratio after weaning, but the extent of growth retardation after weaning was the lowest in piglets supplemented with Chlorella (P<0.01). Supplementation with Spirulina reduced diarrhoea incidence by 50% from day 0 to day 14 (P<0.05). Mucosal architecture at the jejunum was unaffected by Spirulina or Chlorella administration (P>0.10). Shorter ileal villi were measured in SP and CV piglets than in NC piglets (P<0.05). Cytokine expression did not differ between treatments in response to weaning. At day 14, IL-8 expression in the ileum was higher in SP piglets, while IL-1β expression in the jejunum was higher in CV piglets (P<0.05). This study shows that Spirulina administration around weaning alleviates diarrhoea in weaned piglets, without marked modulation of local inflammation.
Effect of starter diet supplementation on rumen epithelial morphology and expression of genes involved in cell proliferation and metabolism in pre-weaned lambs
- D. M. Sun, S.Y. Mao, W.Y. Zhu, J.H. Liu
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- 26 February 2018, pp. 2274-2283
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Starter feeding is usually used in lamb production to improve rumen development and to facilitate the weaning process, but molecular mechanism of which is not well understood. Therefore, the objective of this study is to investigate the effect of starter feeding on the expression of ruminal epithelial genes involved in cell proliferation, apoptosis and metabolism in pre-weaned lambs. We selected eight pairs of 10-day-old lamb twins. One twin was fed ewe milk (M, n=8), while the other was fed ewe milk plus starter (M+S, n=8). The lambs were sacrificed at 56 days age. Results showed that the lambs fed M+S had lower pH in the rumen and a higher concentration of acetate, propionate, butyrate and total volatile fatty acid (VFA). Compared with the M group, the concentration of β-hydroxybutyric acid in plasma had an increased trend, and the concentration of IGF-1 in plasma had an decreased trend in the M+S group. The length, width and surface of rumen papillae increased in the M+S group compared with the M group; this was associated with increased cell layers in the stratum corneum, stratum granulosum and total epithelia. Messenger RNA (mRNA) expression of proliferative genes of cyclin A, cyclin D1 and cyclin-dependent kinase 2 in the ruminal epithelia of M+S lambs was increased compared with M only lambs. The mRNA expression of apoptosis genes of caspase-3, caspase-8, B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax) in the M+S group was decreased compared with M group, but the ratio of Bcl-2 to Bax were not changed between the two groups. Expression of IGF-1 mRNA was decreased, but the mRNA expression of IGF-1 receptor was higher in ruminal epithelia in the M+S group. Furthermore, the mRNA expression of VFA absorption and metabolism genes of β-hydroxybutyrate dehydrogenase isoforms 1 and 3-hydroxy-3-methylglutaryl-CoA lyase had an increased trend in the M+S group than in the M group, but the mRNA expression of 3-hydroxy-3-methylglutaryl-CoA synthase isoform 1, monocarboxylate transporter isoform 1 and putative anion transporter isoform 1 had a decreased trend in the M+S group than in the M group. These results suggest that starter feeding increased proliferation and inhibited apoptosis of ruminal epithelial cells, and may promote the VFA metabolism in ruminal epithelium in pre-weaned lambs. These findings provide new insights into improving rumen development by nutritional intervention strategies in pre-weaned lambs.
Calcium propionate supplementation improves development of rumen epithelium in calves via stimulating G protein-coupled receptors
- X. Z. Zhang, W. B. Chen, X. Wu, Y. W. Zhang, Y. M. Jiang, Q. X. Meng, Z. M. Zhou
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- Published online by Cambridge University Press:
- 26 February 2018, pp. 2284-2291
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In the present study, calcium propionate (CaP) was used as feed additive in the diet of calves to investigate their effects on rumen fermentation and the development of rumen epithelium in calves. To elucidate the mechanism in which CaP improves development of calf rumen epithelium via stimulating the messenger RNA (mRNA) expression of G protein-coupled receptors, a total of 54 male Jersey calves (age=7±1 days, BW=23.1±1.2 kg) were randomly divided into three treatment groups: control without CaP supplementation (Con), 5% CaP supplementation (5% CaP) and 10% CaP supplementation (10% CaP). The experiment lasted 160 days and was divided into three feeding stages: Stage 1 (days 0 to 30), Stage 2 (days 31 to 90) and Stage 3 (days 91 to 160). Calcium propionate supplementation percentages were calculated on a dry matter basis. In total, six calves from each group were randomly selected and slaughtered on days 30, 90 and 160 at the conclusion of each experimental feeding stage. Rumen fermentation was improved with increasing concentration of CaP supplementation in calves through the first 30 days (Stage 1). No effects of CaP supplementation were observed on rumen fermentation in calves during Stage 2 (days 31 to 90). Supplementation with 5% CaP increased propionate concentration, but not acetate and butyrate in calves during Stage 3 (days 91 to 160). The rumen papillae length of calves in the 5% CaP supplementation group was greater than that of Con groups in calves after 160 days feeding. The mRNA expression of G protein-coupled receptor 41 (GPR41) and GPR43 supplemented with 5% CaP were greater than the control group and 10% CaP group in feeding 160 days calves. 5% CaP supplementation increased the mRNA expression of cyclin D1, whereas did not increase the mRNA expression of cyclin-dependent kinase 4 compared with the control group in feeding 160-day calves. These results indicate that propionate may act as a signaling molecule to improve rumen epithelium development through stimulating mRNA expression of GPR41 and GPR43.
Milk production and composition, and progeny performance in young ewes with high merit for rapid growth and muscle and fat accumulation
- C. A. Rosales Nieto, M. B. Ferguson, C. A. Macleay, J. R. Briegel, D. A. Wood, G. B. Martin, R. Bencini, A. N. Thompson
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- 26 February 2018, pp. 2292-2299
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In ewe lambs, acceleration of growth and accumulation of both muscle and fat leads to earlier sexual maturity and better reproductive performance. The next stage in the development of this theme is to test whether these aspects of growth in young ewes affect milk production in their first lactation and the growth of their first progeny. We studied 75 young Merino ewes that had known phenotypic values for depth of eye muscle (EMD) and fat (FAT), and known Australian Sheep Breeding Values for post-weaning weight (PWT) and depths of eye muscle (PEMD) and fat (PFAT). They lambed for the first time at 1 year of age. Their lambs were weighed weekly from birth to weaning at 10 weeks to determine live weight gain and weaning weight. Progeny birth weight was positively associated with live weight gain and weaning weight (P<0.001). The PWT of the mothers was positively associated with birth weight (P<0.01), live weight gain and weaning weight of the progeny (P<0.05); however, these progeny traits were not influenced by EMD, FAT, PEMD, PFAT of the mothers (P>0.05). The PWT of the sire was positively associated with live weight gain (P<0.05) and weaning weight of the progeny (P<0.01). At around day 20 postpartum, we measured milk production and milk composition (fat, protein, lactose, total solids). Milk production was influenced positively by birth type (single or twin; P<0.05) and negatively by birth weight (P<0.05), but not by mother phenotype or genotype, sire genotype of the mother or the sex of the progeny (P>0.05). The concentrations of fat, protein, lactose and total solids in the milk were not affected by the phenotype or genotype of the mothers or of the sires of the mothers, or by the sex of the progeny (P>0.05). We conclude that selection of young Merino ewes for better growth, and more rapid accumulation of muscle and fat, will lead to progeny that are heavier at birth, grow faster and are heavier at weaning. Moreover, milk production and composition do not seem to be affected by the genetic merit of the mother for post-weaning live weight or PEMD or PFAT. Therefore, Merino ewes can lamb at 1 year of age without affecting the production objectives of the Merino sheep industry.
Effect of oak acorn level on colostrum composition and plasma immunoglobulin G of late-pregnant goats and their kids
- H. Jafari, F. Fatahnia, A. Khatibjoo, G. Taasoli, H. Fazaeli
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- 13 March 2018, pp. 2300-2309
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Oak acorn contains high levels of tannins which have capacity to form complexes with proteins and consequently reduce their availability and as a result it could reduce colostrum quality and immunoglobulin (Ig) synthesis. Thus, the aim of this experiment was to investigate the effects of dietary oak (Quercus persica) acorn (OA) level during the last 60 days of pregnancy on colostrum composition and plasma metabolites and IgG level of goats and their kids. In all, 24 multiparous pregnant goats (41.7±2.3 kg BW) were assigned into one of the three experimental diets consisted of control diet (without OA) and diets containing 20% (OA20) or 40% (OA40) OA on dry matter basis. Goats fed OA40 had lower BW change compared with other groups (P⩽0.05). Kids birth weight was not affected by experimental diets (P>0.05). Goats fed OA containing diets had lower plasma glucose, triglyceride and Fe concentrations compared with those fed the control diet (P<0.01). Plasma IgG (P<0.01) and urea (P<0.05) concentrations were lower in goats fed OA40 compared with others. Animals fed OA containing diets had higher plasma alanine aminotransferase than those fed the control diet (P<0.05). Goats fed OA40 produced colostrum with lower fat (P⩽0.05) and lactose (P<0.01) contents compared with other animals. Goats fed OA containing diets had lower colostrum IgG level than those fed the control diet (P⩽0.05). Kids plasma total protein concentration was not affected by experimental diets (P>0.05), whereas kids born from goats fed OA containing diets had lower plasma IgG level compared with the control diet (P<0.01). It is concluded that feeding OA during the last 60 days of pregnancy decreased colostrum quality which may have adverse effect on kid’s survival.
Effects of dietary concentrate composition and linseed oil supplementation on the milk fatty acid profile of goats
- P. Gómez-Cortés, A. Cívico, M. A. de la Fuente, N. Núñez Sánchez, F. Peña Blanco, A. L. Martínez Marín
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- Published online by Cambridge University Press:
- 12 March 2018, pp. 2310-2317
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Milk fat composition can be modulated by the inclusion of lipid supplements in ruminant diets. An interaction between the lipid supplement and the forage to concentrate ratio or the type of forage in the rations may affect milk fat composition. However, little is known about the effects of the starch-to-non-forage NDF ratio in the concentrate and lipid supplementation of goat diets. The aim of this work was to determine the role of dietary carbohydrates in goats rations supplemented with linseed oil on animal performance and milk fatty acid (FA) profile. A total of 16 dairy goats were allocated to two simultaneous experiments (two treatments each), in a crossover design with four animals per treatment and two experimental periods of 25 days. In both experiments alfalfa hay was the sole forage and the forage to concentrate ratio (33:67) remained constant. The concentrate in experiment 1 consisted of barley, maize and soybean meal (concentrate rich in starch), whereas it included soybean hulls replacing 25% of barley and 25% maize in experiment 2 (concentrate rich in NDF). As a result, the starch-to-non-forage NDF ratio was 3.1 in experiment 1 and it decreased to 0.8 in experiment 2. Both concentrates were administered either alone or in combination with 30 g/day of linseed oil. Animal performance parameters were not affected by experimental treatments. In contrast, major changes were observed in milk FA profile due to lipid supplementation and the type of concentrate. Linseed oil significantly raised vaccenic and rumenic acids as well as α-linolenic acid and its biohydrogenation intermediates while decreased medium-chain saturated FA (12:0 to 16:0) in milk fat. Milk fat contents of odd and branched-chain FA and trans-10 18:1 responded differently to linseed oil supplementation according to the concentrate fed.
Physiology and functional biology
Research Article
Transcriptomic and metabolomic responses induced in the livers of growing pigs by a short-term intravenous infusion of sodium butyrate
- E. Ren, X. Chen, S. Yu, J. Xu, Y. Su, W. Zhu
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- Published online by Cambridge University Press:
- 20 February 2018, pp. 2318-2326
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Previous studies showed that butyrate played benefit roles in the health and metabolism of animals. However, little information on the effects of butyrate on the metabolism of piglets at the extraintestinal level is available. The present study investigated transcriptomic and metabolomic responses in the livers of pigs to evaluate the effects of intravenous sodium butyrate (SB) on the body’s metabolism at the extraintestinal level. A total of 12 Duroc×Landrace×Large White growing barrows (60 days of age) fitted with jugular vein cannula were randomly allocated to either the SB group or the control (CO) group. Pigs in the SB group were intravenously infused with 10 ml SB (200 mmol/l) for 7 days, whereas pigs in the CO group were treated with the same amount of saline. The livers of pigs were collected for gene expression and metabolome analyses. The RNA sequencing (RNA-Seq) analysis showed that the mRNA expression of Acyl-CoA synthetase long-chain family member 1 (ACSL1), carnitine palmitoyltransferase 1A (CPT1A), acetyl-CoA acyltransferase 2 (ACAA2) and phosphoenolpyruvate carboxykinase 1 (PCK1) were downregulated (Q<0.05), whereas fatty acid binding protein 1 (FABP1) and cytochrome P450 family 7 subfamily A member 1 (CYP7A1) were upregulated (P<0.05) by SB treatment, indicating a decrease in fatty acid oxidation and gluconeogenesis and an increase in fatty acid transportation and cholesterol metabolism. Gas chromatography-mass spectrometry analysis showed that raffinose was enriched in the SB group compared with the CO group, indicating a decrease in metabolism of galactose. Moreover, SB treatment significantly decreased the concentration of blood cholesterol. The results suggest that a short-term intravenous infusion of SB could modulate hepatic lipid metabolism by decreasing fatty acid oxidation and increasing fatty acid transportation and cholesterol metabolism.
Influence of batch-specific biochemical egg characteristics on embryogenesis and hatching success in farmed pikeperch
- F. J. Schaefer, J. L. Overton, A. Krüger, W. Kloas, S. Wuertz
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- 04 December 2017, pp. 2327-2334
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Low and variable egg quality remains a major issue in aquaculture impeding a reliable and continuous supply of larvae, particularly in emerging species, such as pikeperch, Sander lucioperca. We assessed the influence of batch-specific egg parameters (fatty acid (FA) profiles, cortisol content) on embryo life-stages until hatching (survival at 2, 24, 48, 72 h post fertilization (hpf), hatching rate) in an integrated study under commercial hatchery conditions (44 egg batches). Embryo mortality was elevated until 48 hpf (average 9.8% mortality between 2 and 48 hpf). Embryos surviving until 48 hpf were very likely (98.5%) to hatch successfully. The inherent egg FA composition was variable in-between batches. Total FA content ranged form 66.1 to 171.7 µg/mg (dry matter) total FA. Whereas specific FA ,18 : 0 and 20 : 5(n-3) (eicosapentaenoic acid) of the polar fraction and the ratio of 22 : 6(n-3) (docosahexaenoic acid) to 20 : 5(n-3) within the neutral fraction, were significantly correlated with early embryo development, contents of the respective FA did not differ between high (>90% hatching rate), mid (70% to 90% hatching rate) and low (<70% hatching rate) quality egg batches. Late embryo development and hatching were relatively independent of the FA profiles highlighting stage-dependent influences especially during early embryogenesis. Cortisol levels ranged from 22.7 to 293.2 ng/ml and did not directly explain for mortalities. However, high cortisol was associated with a lower content of specific FA, in particular highly unsaturated FA. These results demonstrate the magnitude of inter-individual differences in the batch-specific biochemical egg composition under stable hatchery conditions and suggest a stress-mediated lack of essential FA, which in turn affects early embryo survival. Surprisingly, embryos are able to cope well with a broad range of inherent egg parameters, which limits their predictive potential for egg quality in general. Still, specific FA profiles of high quality egg batches have potential for formulating species-specific broodstock diets and improving reproductive management in pikeperch.
Rearing conditions and life history influence the progress of gametogenesis and reproduction performances in pikeperch males and females
- A. Khendek, A. Chakraborty, J. Roche, Y. Ledoré, A. Personne, T. Policar, D. Żarski, R. Mandiki, P. Kestemont, S. Milla, P. Fontaine
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- 08 February 2018, pp. 2335-2346
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Pikeperch (Sander lucioperca) is a highly valuable fish in Europe. However, development of aquaculture of pikeperch is highly limited due to seasonality of production. This can be overcome by the controlled reproduction of domesticated fish. The first steps of domestication process may induce changes at anatomical, physiological and molecular levels, thereby affecting a variety of biological functions. While there is abundant literature on their effects on stress and growth for example, these effects on reproduction received limited attention notably in pikeperch, a promising candidate for the development of aquaculture. To answer the question of this life-history effect on pikeperch’s reproduction, we compared two groups (weight: 1 kg) originated from Czech Republic and with the same domestication level (F0). The first group was a recirculating aquatic system cultured one (2 years, previously fed with artificial diet, never exposed to natural changes in temperature/photoperiod conditions) and the second one was a pond cultured group (3 to 4 years, bred under natural feeding and temperature/photoperiod). The wild group successfully spawned, while the farmed one did not spawn at all. During the program, gonadosomatic indexes of both males and females were significantly higher for the wild fish, as well as the sexual steroids. Gene expression analysis revealed significantly lower LH transcript levels at the pituitary level for the farmed females and lower FSH transcript levels at the pituitary level for the males. In conclusion this study showed that the previous rearing conditions (e.g. culture system, age, diet, etc.) alter the further progress of gametogenesis and the reproductive performances in response to controlled photothermal program for both sexes in pikeperch.
Early development and reproductive lifespan of rabbit females: implications of growth rate, rearing diet and body condition at first mating
- E. Martínez-Paredes, L. Ródenas, J. J. Pascual, D. Savietto
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- 20 February 2018, pp. 2347-2355
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Factors influencing early development such as birth weight, nest competition, and the diet received during rearing have been proposed as elements conditioning the future reproductive performance of European rabbit (Oryctolagus cuniculus) females. To evaluate their effects, we followed the life of 1513 females from birth to time of death, culling or censoring (animals alive at a fixed date). Between 0 and 63 days of age 353 females died. From the remaining 1160 females, 864 were chosen based on their birth weight to be transferred from the selection to the production farm. At this farm, 431 females received the control diet (184 g of CP, 381 g of NDF and 11.8 MJ of DE per kg DM), while the other 433 received the fibrous diet (134 g of CP, 436 g of NDF and 10.0 MJ of DE per kg DM). Throughout the rearing period, we checked for the individual live weight and body condition (perirenal fat thickness) at first artificial insemination. Reproductive lifespan was defined as the number of days between the first parturition and the time of death, culling or censoring. Birth weight affected the survival of newborn females during lactation and the presence of a milk spot at birth (related to nest competition) increased the survivability of newborns weighing <45 g (P<0.001). Rearing diet altered the growth curve of females and their body condition at first insemination. The diet also altered the relative risk of death during the rearing period, which was lower among females fed on the fibrous diet (−12.5%; P<0.001). Therefore, a higher number of females fed with this diet reached their reproductive life, directly affecting the productivity measured per housed female. Fatter females at first insemination had smaller litter sizes and a higher risk of being culled than lean ones (P<0.05). In general, the fibrous diet reduced the risk of leaving the herd at early rearing, and both birth weight and perirenal fat thickness affected female’s reproductive lifespan. An excess of fat (positive change in one unit of perirenal fat) at their first insemination represented an increased the risk of death or elimination of 13%.
Welfare, behaviour and health management
Research Article
Relationship between welfare and individual ranging behaviour in commercial free-range laying hens
- H. Larsen, P. H. Hemsworth, G. M. Cronin, S. G. Gebhardt-Henrich, C. L. Smith, J.-L. Rault
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- Published online by Cambridge University Press:
- 24 January 2018, pp. 2356-2364
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Laying hens housed in free-range systems have access to an outdoor range, and individual hens within a flock differ in their ranging behaviour. Whether there is a link between ranging and laying hen welfare remains unclear. We analysed the relationships between ranging by individual hens on a commercial free-range layer farm and behavioural, physiological and health measures of animal welfare. We hypothesised that hens that access the range more will be (1) less fearful in general and in response to novelty and humans, (2) have better health in terms of physical body condition and (3) have a reduced physiological stress response to behavioural tests of fear and health assessments than hens that use the range less. Using radio frequency identification tracking across two flocks, we recorded individual hens’ frequency, duration and consistency of ranging. We also assessed how far hens ventured into the range based on three zones: 0 to 2.4, 2.4 to 11.4 or >11.4 m from the shed. We assessed hen welfare using a variety of measures including: tonic immobility, open field, novel object, human approach, and human avoidance (HAV) behavioural tests; stress-induced plasma corticosterone response and faecal glucocorticoid metabolites; live weight, comb colour, and beak, plumage, footpad, and keel bone condition. Range use was positively correlated with plasma corticosterone response, faecal glucocorticoid metabolites, and greater flight distance during HAV. Hens that used the range more, moved towards rather than away from the novel object more often than hens that ranged less. Distance ranged from the shed was significantly associated with comb colour and beak condition, in that hens with darker combs and more intact beaks ranged further. Overall the findings suggest that there is no strong link between outdoor range usage and laying hen welfare. Alternatively, it may be that hens that differed in their ranging behaviour showed few differences in measures of welfare because free-range systems provide hens with adequate choice to cope with their environment. Further research into the relationship between individual range access and welfare is needed to test this possibility.
Ontogeny of behavioral traits in commercial sows
- K. M. Horback, T. D. Parsons
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- Published online by Cambridge University Press:
- 13 February 2018, pp. 2365-2372
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As the number of gestating sows reared in group housing increases, a better understanding of behavioral traits needed to negotiate these more complex social interactions promises to increase animal welfare and productivity. However, little is known about different behavioral strategies or coping styles in sows, and even less is understood about their ontogeny. To study the development of coping styles in adult gestating sows, 36 sows from the same sire line and same commercial maternal genetics were followed from birth through their second parity. Each animal was observed in a battery of stress-related behavioral tests at 5 weeks, and 3 months of age as well as 24 h postpartum as a parity 1 sow, and during introduction to subsequent gestation period in group housing. The tests at different ages included response to handling, open field exploration, human interaction, litter handling and social interactions with conspecifics. Many of the observed behaviors were correlated during the same period of the animal’s life and provided the motivation for a principal component analysis by age. Using principal component analysis, multiple traits were determined at each age point; at 5 weeks old: active, non-exploratory and cautious explained 82.5% of the variance; at 3 months of age: active, non-exploratory and low fear of humans explained 87.7% of the variance; and as primiparous sows: active, aggressive/dominant and submissive explained 82.0% of the variance. Several individual juvenile behaviors were associated with adult behavioral traits. For instance, the response to handling at 5 weeks was significantly predictive (β=0.4; P<0.05) of the aggressive/dominant trait of parity 1 sows. Taken together results presented here suggest that early behavioral responses of prepuberal gilts during specific instances of elevated environmental or social stress can predict future behavioral response as gestating sows.
Effects of topical anaesthetic and buccal meloxicam on average daily gain, behaviour and inflammation of unweaned beef calves following surgical castration
- D. Van der Saag, S. Lomax, P. A. Windsor, C. Taylor, P. Thomson, E. Hall, P. J. White
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- Published online by Cambridge University Press:
- 26 February 2018, pp. 2373-2381
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Although the pain caused by castration of calves is a significant animal welfare issue for the beef industry, analgesia is not always used for this procedure, largely because of practical limitations associated with injectable forms of pain relief. Novel analgesic formulations have now been developed for livestock to allow topical and buccal administration, offering practical options to improve cattle welfare if shown to be effective. To assess the effects of topical anaesthetic (TA) and buccal meloxicam (BM) on average daily gain (ADG), behaviour and inflammation following surgical castration of beef calves, a total of 50 unweaned bull calves were randomly allocated to: (1) sham castration (SHAM, n=10); (2) surgical castration (C, n=10); (3) surgical castration with pre-operative buccal meloxicam (CBM, n=10); (4) surgical castration with post-operative topical anaesthetic (CTA, n=10); and (5) surgical castration with pre-operative buccal meloxicam and post-operative topical anaesthetic (CBMTA, n=10). Calves were recorded on video for 5 h following treatment and the frequency and duration of specific behaviours displayed by each animal was later observed for 5 min every hour (total of 25 min). Average daily gain was calculated 1, 2 and 6 days following treatment. Scrotal diameter measurements and photographs of wounds were collected from all castrated calves 1, 2 and 6 days following treatment to evaluate inflammation and wound healing. Infrared photographs were used to identify maximum scrotal temperature. Digital photographs were used to visually score wounds on a numerical rating scale of 1 to 5, with signs of inflammation increasing and signs of healing decreasing with progressive scores. Sham castration calves displayed significantly less, and C calves displayed significantly more foot stamps than all other calves (P=0.005). Observations on the duration of time that calves displayed a hypometric ‘stiff gait’ locomotion, indicated that SHAM calves tended to spend no time, C calves tended to spend the greatest time and all other calves tended to spend an intermediate time displaying this behaviour (P=0.06). Maximum scrotal temperatures were lower in CBM and CBMTA calves than C and CTA calves 2 days following treatment (P=0.004). There was no significant effect of treatment on ADG (P=0.7), scrotal diameter (P=0.09) or wound morphology score (P=0.5). These results suggest that TA and BM, alone or in combination, reduced pain and BM reduced inflammation following surgical castration of calves.
The impact of floor type on lameness and hoof health of dairy origin bulls
- V. S. Murphy, D. E. Lowe, F. O. Lively, A. W. Gordon
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- Published online by Cambridge University Press:
- 27 February 2018, pp. 2382-2390
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This study aimed to evaluate the effect of using different floor types to accommodate growing and finishing beef cattle on lameness. In all, 80 dairy origin bulls were blocked according to live weight and breed into 20 groups, and randomly allocated within groups to one of four treatments. The floor types studied were fully slatted flooring throughout the entire experimental period (CS); fully slatted flooring covered with rubber strips throughout the entire experimental period (RS); fully slatted flooring during the growing period and then moved to a solid floor covered with straw bedding during the finishing period (CS-S) and fully slatted flooring during the growing period and then moved to fully slatted flooring covered with rubber strips during the finishing period (CS-RS). The total duration of the study was 204 days. The first 101 days was defined as the growing period, with the remainder of the study defined as the finishing period. During the growing period, there was a tendency for bulls accommodated on CS to have a higher locomotion score compared with those accommodated on RS (P=0.059). However, floor type had no significant effect on locomotion score during the finishing period. There was also no significant effect of floor type on digital dermatitis during both the growing or finishing period. Floor type had no significant effect on swelling at the leg joints at the end of the finishing period. Bulls accommodated on RS had the least probability of bruised soles during both the growing and finishing period (P<0.01). Growing bulls accommodated on CS had significantly greater front heel height net growth compared with those accommodated on RS (P<0.05). However, bulls accommodated on RS had a tendency to have greater front toe net growth compared with those accommodated on CS (P=0.087). Finishing bulls accommodated on CS-RS had the greatest front toe net growth (P<0.001). Heel height net growth was greatest in bulls accommodated on CS-S (P<0.001). Floor type had no significant effect on mean maximum hoof temperature during the growing period. Finishing bulls accommodated on CS-S had a significantly lower mean maximum hoof temperature compared with those accommodated on any other floor type (P<0.001). The study concluded that rubber flooring is a suitable alternative to fully slatted flooring, reducing the prevalence of bruised soles. Despite greater toe net growth in bulls accommodated on rubber flooring, there was no effect of floor type on locomotion score, suggesting that increased toe net growth does not adversely affect walking ability. In addition, although mean maximum hoof temperature was lowest in bulls accommodated on straw bedding, there was no evidence to suggest this is indicative of improved hoof health.
Livestock farming systems
Research Article
Performance, profitability and greenhouse gas emissions of alternative finishing strategies for Holstein-Friesian bulls and steers
- B. Murphy, P. Crosson, A. K. Kelly, R. Prendiville
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- Published online by Cambridge University Press:
- 06 February 2018, pp. 2391-2400
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Modifying finishing strategies within established production systems has the potential to increase beef output and farm profit while reducing greenhouse gas (GHG) emissions. Thus, the objectives of this study were to investigate the effects of finishing duration on animal performance of Holstein-Friesian (HF) bulls and steers and evaluate the profitability and GHG emissions of these finishing strategies. A total of 90 HF calves were assigned to a complete randomised block design; three bull and three steer finishing strategies. Calves were rotationally grazed in a paddock system for the first season at pasture, housed and offered grass silage ad libitum plus 1.5 kg DM of concentrate per head daily for the first winter and returned to pasture for a second season. Bulls were slaughtered at 19 months of age and either finished indoors on concentrates ad libitum for 100 days (19AL), finished at pasture supplemented with 5 kg DM of concentrate per head daily for 100 (19SP) or 150 days (19LP). Steers were slaughtered at 21 months of age and finished at pasture, supplemented with 5 kg DM of concentrate per head daily for 60 (21SP) and 110 days (21LP) or slaughtered at 24 months of age and finished indoors over the second winter on grass silage ad libitum plus 5 kg DM of concentrate per head daily (24MO). The Grange Dairy Beef Systems Model and the Beef Systems Greenhouse Gas Emissions Model were used to evaluate profitability and GHG emissions, respectively. Average daily gain during the finishing period (P<0.001), live weight at slaughter (P<0.01), carcass weight (P<0.05) and fat score (P<0.001) were greater for 19AL than 19SP and 19LP, respectively. Similarly, concentrate dry matter intake was greater for 19AL than 19SP; 19LP was intermediate (P<0.001). Live weight at slaughter (P<0.001), carcass weight (P<0.001), conformation score (P<0.05) and fat score (P<0.001) were greater for 24MO than 21SP and 21LP, respectively. During the finishing period concentrate dry matter intake was greater for 21LP than 21SP with 24MO intermediate; 542, 283 and 436 kg DM, respectively. Although pasture-based finishing strategies had lower gross output values, concentrate feed costs were also reduced thus net margin was greater than indoor finishing strategies. Reducing concentrate input increased GHG emissions for bulls and steers slaughtered at the same age, respectively. Although prolonging the finishing duration reduced GHG emissions for bull and steer production systems, finishing bulls and steers over a longer period at pasture did not enhance animal performance and profit.
Management practices associated with reproductive performance in Holstein cows on large commercial dairy farms
- I. Fodor, Zs. Abonyi-Tóth, L. Ózsvári
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- Published online by Cambridge University Press:
- 13 February 2018, pp. 2401-2406
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As a result of the increase in herd size and the intensification of production, the complexity of reproductive management has been growing in dairy herds. The aim of our study was to examine the associations of management practices and reproductive performance in Holstein cows on large commercial dairy farms. Management practices applied to cows were surveyed between 22 May and 6 November 2015 in 34 large Holstein-Friesian dairy herds in Hungary. Individual data of 23 784 cows that calved between 1 January 2014 and 31 December 2014 in the surveyed herds were gathered. Associations between the management practices and the reproductive parameters were analyzed by mixed effects models. Regarding heat abatement we found that ventilation with sprinklers was associated with the shortest breeding interval (P<0.01), the shortest calving to conception interval (P<0.01), and the highest odds of being pregnant by 200 days in milk (P<0.01). Solely ventilation showed similar (P>0.05) results to lack of heat stress protection. It was also revealed, that lack of a well-established voluntary waiting period (VWP) or a VWP shorter than 50 days was associated with less days to first service (P<0.01), shorter breeding interval (P<0.01) and calving to conception interval (P<0.05), as well as higher odds of carrying a calf by 200 days in milk (P<0.01) compared with those using a VWP of at least 50 days. Those farms that applied transrectal ultrasonography were more likely to use ventilation with sprinklers (P<0.05), hormonal synchronization (P<0.01) and to perform early pregnancy diagnosis followed by pregnancy recheck (P<0.05). The application of transrectal ultrasonography with one of the aforementioned practices was associated with reduced days to first service (P<0.05), shorter breeding interval (P<0.05) and higher odds of pregnancy at 200 days in milk (P<0.05). Our study highlights the management practices most closely related to improved reproductive performance, which are, therefore, suggested to be applied on dairy farms, considering the local circumstances of the individual farms.