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See detailThermal manipulation of the embryo modifies the physiology and body composition of broiler chickens reared in floor pens without affecting breast meat processing quality.
Loyau, T.; Berri, C.; Bedrani, L. et al

in Journal of animal science (2013), 91(8), 3674-85

Selection in broiler chickens has increased muscle mass without similar development of the cardiovascular and respiratory systems, resulting in limited ability to sustain high ambient temperatures. The ... [more ▼]

Selection in broiler chickens has increased muscle mass without similar development of the cardiovascular and respiratory systems, resulting in limited ability to sustain high ambient temperatures. The aim of this study was to determine the long-lasting effects of heat manipulation of the embryo on the physiology, body temperature (Tb), growth rate and meat processing quality of broiler chickens reared in floor pens. Broiler chicken eggs were incubated in control conditions (37.8 degrees C, 56% relative humidity; RH) or exposed to thermal manipulation (TM; 12 h/d, 39.5 degrees C, 65% RH) from d 7 to 16 of embryogenesis. This study was planned in a pedigree design to identify possible heritable characters for further selection of broiler chickens to improve thermotolerance. Thermal manipulation did not affect hatchability but resulted in lower Tb at hatching and until d 28 post-hatch, with associated changes in plasma thyroid hormone concentrations. At d 34, chickens were exposed to a moderate heat challenge (5 h, 32 degrees C). Greater O2 saturation and reduced CO2 partial pressure were observed (P < 0.05) in the venous blood of TM than in that of control chickens, suggesting long-term respiratory adaptation. At slaughter age, TM chickens were 1.4% lighter and exhibited 8% less relative abdominal fat pad than controls. Breast muscle yield was enhanced by TM, especially in females, but without significant change in breast meat characteristics (pH, color, drip loss). Plasma glucose/insulin balance was affected (P < 0.05) by thermal treatments. The heat challenge increased the heterophil/lymphocyte ratio in controls (P < 0.05) but not in TM birds, possibly reflecting a lower stress status in TM chickens. Interestingly, broiler chickens had moderate heritability estimates for the plasma triiodothyronine/thyroxine concentration ratio at d 28 and comb temperature during the heat challenge on d 34 (h(2) > 0.17). In conclusion, TM of the embryo modified the physiology of broilers in the long term as a possible adaptation for heat tolerance, without affecting breast meat quality. This study highlights the value of 2 new heritable characters involved in thermoregulation for further broiler selection. [less ▲]

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See detailGenetic analysis of pig survival in a crossbred population
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Journal of Animal Science (2013), 91(E-Suppl.2), 193

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See detailEstimation of genetic parameters for birth weight, preweaning mortality, and hot carcass weight of crossbred pigs
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Journal of Animal Science (2013), 91

Genetic parameters for birth weight (BWT), preweaning mortality (PWM), and hot carcass weight (HCW) were estimated for a crossbred pig population to determine if BWT could be used as an early predictor ... [more ▼]

Genetic parameters for birth weight (BWT), preweaning mortality (PWM), and hot carcass weight (HCW) were estimated for a crossbred pig population to determine if BWT could be used as an early predictor for later performances. Sire genetic effects for those traits were estimated to determine if early selection of purebred sires used in crossbreeding could be improved. Data were recorded from one commercial farm between 2008 and 2010. Data were from 24,376 crossbred pigs from Duroc sires and crossbred Large White × Landrace dams and included 24,376 BWT and PWM records, and 13,029 HCW records. For the analysis, PWM was considered as a binary trait (0 for live or 1 for dead piglet at weaning). A multi-trait threshold-linear animal model was used, with animal effect divided into sire genetic and dam effects; the dam effects included both genetic and environmental variation due to the absence of pedigree information for crossbred dams. Fixed effects were sex and parity for all traits, contemporary groups for BWT and HCW, and age at slaughter as a linear covariable for HCW. Random effects were sire additive genetic, dam, litter, and residual effects for all traits, and contemporary group for PWM. Heritability estimates were 0.04 for BWT, 0.02 for PWM, and 0.12 for HCW. Ratio between sire genetic and total estimated variances was 0.01 for BWT and PWM, and 0.03 for HCW. Dam and litter variances explained respectively 14% and 15% of total variance for BWT, 2% and 10% for PWM, and 3% and 8% for HCW. Genetic correlations were −0.52 between BWT and PWM, 0.55 between BWT and HCW, and -0.13 between PWM and HCW. Selection of purebred sires for higher BWT of crossbreds may slightly improve survival until weaning and final market weight at the commercial level. [less ▲]

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See detailGenetic analysis of longitudinal measurements of feed intake in Piétrain sire lines
Dufrasne, Marie ULg; Jaspart, Véronique; Wavreille, José et al

in Journal of Animal Science (2013), 91(E-Suppl.2), 293

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See detailUse of medium without reducing agent for in vitro fermentation studies by bacteria isolated from pig intestine
POELAERT, Christine ULg; Boudry, Christelle ULg; Portetelle, Daniel ULg et al

in Journal of Animal Science (2012, December), 90(Supplement 4), 387-389

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See detailInfluence of fermentable carbohydrates or protein on large intestinal and urinary metabolomic profiles in piglets
Pieper, R; Neumann, K; Kröger, S et al

in Journal of Animal Science (2012), 90(Supplement 4), 34-36

It was recently shown that variations in the ratio of dietary fermentable carbohydrates (fCHO) and fermentable protein (fCP) differentially affect large intestinal microbial ecology and the mucosal ... [more ▼]

It was recently shown that variations in the ratio of dietary fermentable carbohydrates (fCHO) and fermentable protein (fCP) differentially affect large intestinal microbial ecology and the mucosal response. Here we investigated the use of mass spectrometry to profile changes in metabolite composition in colon and urine associated with variation in dietary fCHO and fCP composition and mucosal physiology. Thirty-two weaned pigletswere fed 4 diets in a 2 × 2 factorial design with low fCP and low fCHO, low fCP and high fCHO, high fCP and low fCHO, and high fCP and high fCHO. After 21 to 23 d, all pigs were euthanized and colon digesta and urine metabolite profiles were obtained by mass spectrometry. Analysis of mass spectra by partial least squares approach indicated a clustering of both colonic and urinary profiles for each pig by feeding group. Metabolite identification and annotation using the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways revealed increased abundance of metabolites associated with arachidonic acid metabolism in colon of pigs fed a high concentration of fCP irrespective of dietary fCHO. Urinary metabolites did not show as clear patterns. Mass spectrometry can effectively differentiate metabolite profiles in colon contents and urine associated with changes in dietary composition. Whether metabolite profiling is an effective tool to identify specific metabolites (biomarkers) or metabolite profiles associated with gut function and integrity needs further elucidation. [less ▲]

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See detailEstimation of genetic parameters for birth weight, pre-weaning mortality and hot carcass weight in a crossbred population of pigs
Dufrasne, Marie ULg; Misztal, Ignacy; Tsuruta, Shogo et al

in Journal of Animal Science (2012), 90(E-Suppl.3), 721

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See detailConstruction of individual breeding values for feed intake of Piétrain boars based on mean pen feed intake, weight and weight gain test station records
Dufrasne, Marie ULg; Jaspart, Véronique; Wavreille, José et al

in Journal of Animal Science (2011), 89(E-Suppl.1), 474-475

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See detailUsing test station and on-farm data for the genetic evaluation of Piétrain boars used on Landrace sows for growth performance
Dufrasne, Marie ULg; Rustin, Maité; Jaspart, Véronique et al

in Journal of Animal Science (2011), 89

The aim of this study was to develop a new genetic evaluation model to estimate the genetic merit of boars for growth based on 1) performance of their crossbred progeny fattened in the test station and 2 ... [more ▼]

The aim of this study was to develop a new genetic evaluation model to estimate the genetic merit of boars for growth based on 1) performance of their crossbred progeny fattened in the test station and 2) their own performance or those of relatives from the on-farm testing system. The model was a bivariate random regression animal model with linear splines and was applied to Piétrain boars from the Walloon Region of Belgium mated with Landrace sows. Data contained 1) 12,610 BW records from the test station collected on 1,435 crossbred pigs from Piétrain boars and Landrace sows, and 2) 52,993 BW records from the on-farm testing system collected on 50,670 pigs with a breed composition of at least 40% Piétrain or Landrace. Since 2007, 56 Piétrain boars have been tested in the station. Data used to estimate variance components and breeding values were standardized for the age to take into account heterogeneity of variances and then pre-adjusted at 210 d of age to put all records on the same scale. Body weight records from the test station and from the on-farm testing system were considered as 2 different traits. The heterosis effect was modeled as fixed regression on the heterozygosity coefficient. As all test station animals were similarly crossbred, smaller variation in heterozygosity caused the sampling error of the regression estimate at 210 d to be larger in the test station than in on-farm data with estimates of 28.35 ± 14.55 kg and 9.02 ± 0.67 kg, respectively. Therefore, the most likely reason for the large differences in estimates was sampling. Heritability estimates ranged from 0.37 to 0.60 at 210 and 75 d, respectively, for test station BW and from 0.42 to 0.60 at 210 d and 175 d, respectively, for on-farm BW. Genetic correlation decreased when the age interval between records increased, and were greater between ages for test station than for on-farm data. Genetic correlations between test station and on-farm BW at the same age were high: 0.90 at 175 d and 0.85 at 210 d. For the 56 boars tested in the station, the average reliability of their EBV for ADG between 100 and 210 d was improved from 0.60 using only test station data to 0.69 using jointly test station and on-farm data. Based on these results, the new model developed was considered as a good method of detection of differences in growth potential of Piétrain boars based on test station and on-farm data. [less ▲]

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See detailNew method to combine molecular and pedigree relationships
Bömcke, Elisabeth ULg; Soyeurt, Hélène ULg; Szydlowski, Maciej et al

in Journal of Animal Science (2011), 89

Relationship coefficients are traditionally based on pedigree data. Today, with the development of molecular techniques, they are often completely replaced by coefficients calculated from molecular data ... [more ▼]

Relationship coefficients are traditionally based on pedigree data. Today, with the development of molecular techniques, they are often completely replaced by coefficients calculated from molecular data. Examples are relationships from microsatellites for biodiversity studies but also genomic relationships from SNP as currently used in genomic prediction of breeding values. There are, however, many situations in which optimal combination of both sources would be the best solutions. Obviously, this is the case for incompletely genotyped populations, but also when pedigree information is sparse. Also, markers, even dense ones, do not reflect the whole genome and therefore give only an incomplete picture of relationships. The main objective of this study was therefore to develop a method to calculate a relationship matrix by the combination of molecular and pedigree data. It will be useful for all situations where pedigree and molecular data are available. In this study, based on simulations of pedigree and marker data, we used partial least squares regression and linear regression to combine total allelic relationship coefficients calculated for each marker with additive relationship coefficients calculated from incomplete pedigree. The results showed that the greatest advantage of this method, compared with the one that replaces a part of the pedigree-based relationship matrix by a genomic relationship matrix, is that adding the partial pedigree data allows for the correction of the molecular coefficient for the ungenotyped part of the genome. [less ▲]

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See detailDifferences in carbohydrate composition of barley varieties influence Salmonella transmission among pen mate weaned piglets
Bindelle, Jérôme ULg; Pieper, Robert; Marshall, Jason et al

in Journal of Animal Science (2010), 88(E2), 284

Indigestible carbohydrate (CHO) composition can vary markedly between barley varieties. They induce changes in intestinal ecophysiology and enhance growth of health-promoting bacteria. An experiment was ... [more ▼]

Indigestible carbohydrate (CHO) composition can vary markedly between barley varieties. They induce changes in intestinal ecophysiology and enhance growth of health-promoting bacteria. An experiment was undertaken to assess whether these changes could influence Salmonella typhimurium (ST) infection in pigs and transmission between penmates. A challenge study was undertaken using 84 recently weaned piglets divided in 12 pens, and fed one of the 4 experimental diets (3 pens/diet), according to the barley variety. Three hullless and one hulled varieties were chosen according to their differing CHO composition (amylose/amylopectin, β-glucan, and insoluble non-starch polysaccharides). After 14 d of adaptation, 2 pigs per pen (Trojan pigs, TrojP) were orally infected (8.0 log cfu/animal) with a low virulent, nalidixic acid and novobiocin resistant ST strain. The other animals were considered as Contact pigs (ConP) to assess ST transmission. Over 5 d following inoculation, pigs were monitored for detection of ST in the feces using plate counts. On d 6, 2 TrojP and 2 ConP per group were killed and intestinal samples as well as organ samples (liver, spleen, and lymph nodes) were analyzed for ST. The results showed that in TrojP, the cereal variety had no influence on ST fecal shedding over time and gastrointestinal tract (GIT) colonization. All pigs were positively tested for ST. Translocation of ST to lymph nodes was observed frequently but not to other organs. In ConP, compared with hulled barley, hulless barleys reduced the number of animals shedding ST (P < 0.05 for d 2) and the number of ST (cfu/g) in cecum on d 6 (P < 0.01). Although hulless barleys did not protect against colonization when directly challenged at a high oral dose, these barleys may be useful to reduce natural ST transmission among penmates. [less ▲]

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See detailCorrelative responses for carcass and meat quality traits to selection for ovulation rate or prenatal survival in French Large White pigs.
Rosendo, A.; Druet, Tom ULg; Pery, C. et al

in Journal of Animal Science (2010), 88(3), 903-11

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See detailIn vitro evaluation of the fermentation characteristics in the pig intestines of hulless barleys differing in β-glucan content
Jha, Rajesh; Bindelle, Jérôme ULg; Rossnagel, Brian et al

in Journal of Animal Science (2009), 87(E-Suppl. 3), 103

Non-starch polysaccharides (NSP) in isolated form, especially β-glucans, are reported to have prebiotic effects in pigs. However, little information is available on the possible functional properties of ... [more ▼]

Non-starch polysaccharides (NSP) in isolated form, especially β-glucans, are reported to have prebiotic effects in pigs. However, little information is available on the possible functional properties of these NSP when the latter are still present in the fibrous matrix of whole cereals. Hulless barleys (HB) are good sources of β-glucans and the content is quite variable among varieties. In order to evaluate the potential of HB as functional feeds, an in vitro experiment was carried out to study the fermentation characteristics of 6 HB varieties varying in their β-glucan contents (36-99 g/kg DM) in comparison to 3 hulled barleys and 5 oats. After a pepsin-pancreatin hydrolysis, the ingredients were incubated in a buffer solution containing minerals and pig feces as inoculum. The accumulated gas production, proportional to the amount of fiber fermented, was measured for 48 h and modeled. Short-chain fatty acid (SCFA) and ammonia concentration were measured in the fermented solutions. A cereal type effect (P < 0.05) was observed on the fermentation kinetics parameters. Rates of degradation and total gas productions were higher in HB than in oats (P < 0.05) but no difference was observed between HB varieties. On the contrary, differences were found between HB for lag time and rate of degradation. The production of SCFA was also higher with HB (6.1 mMol/g DM incubated; P < 0.05) than with hulled barleys and oats (4.9 and 2.9 mMol/g DM incubated respectively). In contrast, oats generated higher ammonia (P <0.05) production (1.4 mMol/g DM incubated, on average) than barley (1.0 mMol/g). In conclusion, HB are better fermented in vitro, produce more beneficial (SCFA) and less harmful (ammonia) metabolites and have a better potential than other cereal species to modulate gut microbiota and improve gut health. [less ▲]

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See detailVarietal effects of barley carbohydrate composition on digestibility, fermentability and microbial ecophysiology in an in vitro model of the pig gastrointestinal tract.
Bindelle, Jérôme ULg; Pieper, Robert; Rossnagel, Brian et al

in Journal of Animal Science (2009), 87(E-Suppl. 3), 93

Carbohydrate (CHO) composition can vary markedly between barley varieties. Their influence on digestibility, intestinal fermentation and microbiota in pigs was studied in vitro. Ten hulless (HLB) and 6 ... [more ▼]

Carbohydrate (CHO) composition can vary markedly between barley varieties. Their influence on digestibility, intestinal fermentation and microbiota in pigs was studied in vitro. Ten hulless (HLB) and 6 hulled barleys (HB) differing in B-glucan, non-starch polysaccharides (NSP), starch content, and amylose/amylopectin ratio, were hydrolyzed enzymatically and subsequently fermented for 72h. CHO fermentation kinetics were modeled; microbial composition and short-chain fatty acid (SCFA) production were analyzed. In HLB, in vitro DM digestibility was positively correlated to starch and amylopectin content and CP digestibility to amylopectin (P<0.05), whereas both were negatively correlated to insoluble NSP (P<0.05). Rate of fermentation was different (P<0.01) between barley types but not correlated to the CHO composition. However, high B-glucan contents induced faster fermentation (P<0.05, HLB; P<0.10, HB). SCFA molar ratios after fermentation of HLB were higher in propionate and branchedchain fatty acids and lower in acetate compared to HB (P<0.01). With HLB, amylose content was positively correlated to butyrate production and negatively to propionate, which was positively correlated to soluble NSP content (P<0.01). In HB, no correlation between SCFA production and the carbohydrate composition was found. TRFLP analysis revealed that Bacteroides and members of Clostridium cluster XIVa were differentially affected in HLB compared to HB as well as by the type and source of CHO. Microbial profiles were also correlated (P<0.05) to SCFA and fermentation parameters but response differed significantly between HB and HLB. The strongest correlation between CHO structure, microbial abundance and fermentation parameters was evident in HLB. Hulless barleys may offer the greatest opportunity to improve gut health in pigs. [less ▲]

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See detailInfluence of source and levels of dietary fiber on in vivo nitrogen excretion pathways in pigs and in vitro fermentation and protein synthesis by fecal bacteria
Bindelle, Jérôme ULg; Buldgen, André; Delacollette, Maud et al

in Journal of Animal Science (2009), 87

The inclusion of dietary fiber (DF) in diets has been suggested as a way to reduce ammonia emission in pig barns because it contributes to a shift in N excretion from urine to feces due to enhanced ... [more ▼]

The inclusion of dietary fiber (DF) in diets has been suggested as a way to reduce ammonia emission in pig barns because it contributes to a shift in N excretion from urine to feces due to enhanced bacterial growth in the intestines. This study compared an in vitro method to measure bacterial protein synthesis during fermentation to in vivo N excretion shift induced by diets differing in DF concentrations and solubility. The first experiment measured the effect of graded concentrations of sugar beet pulp (SBP; 0, 10, 20 and 30%) in corn-soybean meal-based diets on in vivo N excretion partitioning between urine and feces. A second experiment investigated the replacement of SBP, rich in soluble DF, by oat hulls (OH), rich in insoluble DF (20:0; 10.5:10.5; 0:22%, respectively). In parallel, the fermentation characteristics of the dietary carbohydrates not digested in the small intestine was evaluated in an in vitro gas test, based on their incubation with colonic microbiota, using a mineral buffer solution enriched with 15N. The N originating from the buffer solution incorporated into the bacterial proteins (BNI) was measured when half of the final gas volume was produced (T/2: 8.5 to 14.5 h of fermentation) and after 72 h of fermentation. Short-chain fatty acids (SCFA) were determined in the liquid phase. In the first experiment, the inclusion of SBP linearly decreased urinary N excretion from 0.285 to 0.215 g N excreted in urine per g N ingested and urinary-N:fecal–N excretion ratio from 2.171 to 1.177 (P < 0.01). In the second experiment, the substitution of SBP by OH linearly increased urinary-N:fecal–N excretion ratio (P = 0.009). Unlike SCFA production, BNI was greater at T/2 than at 72 h of fermentation. Sugar beet pulp enhanced BNI linearly (P < 0.001): 2.01, 2.06 and 2.35 mg g-1 diet with 10, 20 and 30% SBP, respectively, as compared to 1.51 mg for the control diet. The substitution of SBP by OH decreased BNI (P < 0.01). With the exception of final gas production, all in vitro kinetics characteristics and BNI were correlated to in vivo N excretion parameters and regression equations for the prediction of N excretion pathways from in vitro data were identified. Even if the presence of resistant starch in the diet might alter the composition of the fibrous residue that is fermented, it can be concluded that the in vitro method is a possible useful tool for the formulation of diets reducing the effects of pig production on the environment. [less ▲]

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See detailApplication of forensic science technique to the management of an endangered horse population
Bömcke, Elisabeth ULg; Gengler, Nicolas ULg

in Journal of Animal Science (2008), 86(E-suppl.2), 433

Implementing conservation strategies needs the knowledge of relationships inside the concerned population. The aim of the study was to find tools to help breeders to manage their horse population. The ... [more ▼]

Implementing conservation strategies needs the knowledge of relationships inside the concerned population. The aim of the study was to find tools to help breeders to manage their horse population. The Skyros pony is an indigenous Greek breed. The breed risk status is defined as critical-maintained according to the criteria from the Food and Agriculture Organization. Partial pedigree information is available, but its quality is poor as the average number of generation-equivalents is under 0.8 for the first known generation and under 1.4 for the second to the fifth. Further, 99 living individuals were genotyped at 16 microsatellite loci in order to check the registered parentage. For ungenotyped animals, conditional expectation of gene contents was calculated given molecular and pedigree data. As said in other studies, the animal genetics literature often seems unaware of relevant developments in human genetics (and conversely). In this study, an approach called Familial Searching was tested. This is used in forensic science, in addition to matching DNA evidence directly to criminal profiles, to search for people (present in a database) who are related to an individual that left DNA evidence at a scene of crime. This method is based on the calculation of likelihood ratios (LR) between genotype of an individual and genotypes of each other individuals of the database. The pedigree was used as ‘local’ prior information, i.e. relating to specific pairs of individuals. General knowledge about the studied population (generation interval, sexual maturity, …) was considered as ‘global’ prior information. Including prior information reduced the number of comparisons from over 50%. First results showed that the parents were always classified into the 5 highest LR. These results simplified parentage verifications, it allowed the detection of 90% of false parentage (LR=0). New links were created in the pedigree through detection of unregistered parents, what involved a reduction of the percentage of animals with one or both unknown parents and consequently an increase of the number of generation-equivalents. The pedigree of the breed was thus improved. [less ▲]

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See detailFermentable non-starch polysaccharides increase the excretion of bacterial proteins in the pig's faeces and reduce urinary N excretion.
Bindelle, Jérôme ULg; Leterme, Pascal; Wavreille, José et al

in Journal of Animal Science (2008), 86(suppl. 3), 101

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See detailEffect Of Rumen-Degradable Protein Balance Deficit On Voluntary Intake, Microbial Protein Synthesis, And Nitrogen Metabolism In Growing Double-Muscled Belgian Blue Bulls Fed Corn Silage-Based Diet
Valkeners, Damien; Thewis, André ULg; Van Laere, Marc et al

in Journal of Animal Science (2008), 86(3), 680-690

Two trials were conducted to evaluate the effect of rumen-degradable protein balance (OEB) deficit on voluntary intake (trial 1), microbial protein synthesis, andNmetabolism (trial 2) in growing ... [more ▼]

Two trials were conducted to evaluate the effect of rumen-degradable protein balance (OEB) deficit on voluntary intake (trial 1), microbial protein synthesis, andNmetabolism (trial 2) in growing doublemuscled Belgian Blue bulls. In trial 1, six bulls (339 ± 26 kg of initial BW) were used in a replicated 3 × 3 Latin square and received a diet of 60% corn silage and 40% concentrate with ad libitum intake (DM basis). Three concentrates were formulated by adding urea at the expense of barley to give similar dietary contents of intestinal digestible proteins, NE for fattening, and fermentable OM, but with different levels of OEB. Thus, 2 levels of OEB deficit (−23.7 and −9.2 g of OEB/kg of DM) were compared with a diet providing a slight OEB surplus (5.3 g of OEB/kg of DM). Voluntary DMI decreased linearly (P = 0.02) with decreasing rumen-degradable protein balance. This decrease in intake could explain the linear decrease in ADG observed when negative OEB diets were fed. In trial 2, six bulls (304 ± 12 kg of initial BW) with cannulas in the rumen and proximal duodenum were used in a replicated 3 × 3 Latin square and fed diets similar to those used in trial 1 at an intake level of 85 g of DM/kg of BW0.75. Diurnal variations of ruminal NH3-N and plasma urea-N concentrations were greatly influenced by the level of OEB in the diet. No differences in NDF and starch degradation in the rumen, microbial N flow at the duodenum, or efficiency of microbial protein synthesis in the rumen were noted among the levels of OEB in diets. The reductions of the OEB value from 5.3 g/kg of DM to −9.2 g/ kg of DM and −23.7 g/kg of DM were associated with reductions of 26.5 and 48.8% in urinary Noutput. Absolute amounts of N retained by the bulls increased significantly with the level of OEB in diets. Indeed, 51.4% of the incremental supply of N was excreted between −23.7 and −9.2 g of OEB/kg of DM diets, and 74.6% of the incremental supply of N was excreted between −9.2 and 5.3 g of OEB/kg of DM diets. Feeding diets characterized by an adequate intestinal digestible protein supply and a OEB close to −10 g of OEB/kg of DM could be a feeding strategy to reduce N losses from the farm with little effect on the animal performance and voluntary intake. Reduced OEB may reduce N excretion in the environment but may also result in decreased N retention. [less ▲]

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See detailCorrelated responses of pre- and postweaning growth and backfat thickness to six generations of selection for ovulation rate or prenatal survival in French Large White pigs.
Rosendo, A.; Canario, L.; Druet, Tom ULg et al

in Journal of Animal Science (2007), 85(12), 3209-17

Correlated effects of selection for components of litter size on growth and backfat thickness were estimated using data from 3 pig lines derived from the same base population of Large White. Two lines ... [more ▼]

Correlated effects of selection for components of litter size on growth and backfat thickness were estimated using data from 3 pig lines derived from the same base population of Large White. Two lines were selected for 6 generations on either high ovulation rate at puberty (OR) or high prenatal survival corrected for ovulation rate in the first 2 parities (PS). The third line was an unselected control (C). Genetic parameters for individual piglet BW at birth (IWB); at 3 wk of age (IW3W); and at weaning (IWW); ADG from birth to weaning (ADGBW), from weaning to 10 wk of age (ADGPW), and from 25 to 90 kg of BW (ADGT); and age (AGET) and average backfat thickness (ABT) at 90 kg of BW were estimated using REML methodology applied to a multivariate animal model. In addition to fixed effects, the model included the common environment of birth litter, as well as direct and maternal additive genetic effects as random effects. Genetic trends were estimated by computing differences between OR or PS and C lines at each generation using both least squares (LS) and mixed model (MM) methodology. Average genetic trends for direct and maternal effects were computed by regressing line differences on generation number. Estimates of direct and maternal heritabilities were, respectively, 0.10, 0.12, 0.20, 0.24, and 0.41, and 0.17, 0.33, 0.32, 0.41, and 0.21 (SE = 0.03 to 0.04) for IWB, IW3W, IWW, ADGBW, and ADGPW. Genetic correlations between direct and maternal effects were moderately negative for IWB (-0.21 +/- 0.18), but larger for the 4 other traits (-0.59 to -0.74). Maternal effects were nonsignificant and were removed from the final analyses of ADGT, AGET, and ABT. Direct heritability estimates were 0.34, 0.46, and 0.21 (SE = 0.03 to 0.05) for ADGT, AGET, and ABT, respectively. Direct and maternal genetic correlations of OR with performance traits were nonsignificant, with the exception of maternal correlations with IWB (-0.28 +/- 0.13) and ADGPW (0.23 +/- 0.11) and direct correlation with AGET (-0.23 +/- 0.09). Prenatal survival also had low direct but moderate to strong maternal genetic correlations (-0.34 to -0.65) with performance traits. The only significant genetic trends were a negative maternal trend for IBW in the OR line and favorable direct trends for postweaning growth (ADGT and AGET) in both lines. Selection for components of litter size has limited effects on growth and backfat thickness, although it slightly reduces birth weight and improves postweaning growth. [less ▲]

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