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Preweaning survival and growth are compromised in litters with larger numbers of piglets. We evaluated two approaches for altering initial nursing with the goal to improve access to colostrum by groups of piglets that are known to have reduced access to colostrum. Therefore, we temporarily (1.5 h) removed either the heaviest six piglets in the litter (WT) or the first half of the piglets born (ORD) to provide a short period of nursing with reduced competition for the remaining piglets. We found that WT piglets were heavier (P ≤ 0.05) at 7 d after farrowing and gained more body weight (BW) from farrowing to day 7 than control (CON) piglets which were raised in litters with ad libitum nursing during the same period. Further, we found that the heaviest piglets consumed more (P < 0.001) colostrum and gained more (P < 0.001) BW during the preweaning period but did not have (P > 0.10) greater immunocrits. Although ORD piglets had similar colostrum intake, immunocrits, and preweaning weights as controls, we found that overall the piglets born in the first half of litters had greater (P < 0.01) immunocrits than piglets born in the last half of the litter. Therefore, both birth weight and birth order have effects on traits that are important for prenatal growth and survival, but they differ in that birth weight is more closely related to colostrum intake and birth order affects immunocrit. [ABSTRACT FROM AUTHOR]

Farrowing pens with temporary crating have been developed as a compromise between conventional farrowing crates and pens to better accommodate the welfare of both sow and piglets during lactation. However, not much is known about the behavioral and physiological consequences of early removal of confinement on the sow and piglets during lactation. The aim of this study was to assess the effects on sow and piglet performance of temporary crating until 3-d postpartum at 2 times points, immediately after confinement removal and 25 d into lactation. Sows were crated from 5-d prepartum either to weaning (permanently crated—PC group; N =14) or to D3 (83.0 ± 1.3 h) postpartum (Temporarily crated - TC group N = 13). Sow postural changes, activity, cortisol and IgA concentrations, and piglet body weight gain and behavior were assessed on D4 and on D25 postpartum, whereas piglet mortality was assessed throughout lactation. Data were analyzed using PROC GLM and PROC GENMOD of SAS. On D4 postfarrowing, TC sows were more active (10.9% vs. 7.1%; SEM: 0.8; P = 0.002), rolled more frequently (21.3% vs. 14.4%; SEM: 1.6; P = 0.008), and had lower IgA concentrations (139.7 vs. 75.2 μg/mL; SEM: 20.3; P = 0.040) than PC sows. No effects of housing were found (P > 0.05) on standing-to-lying movement or cortisol concentrations. No differences for any variables were found (P > 0.05) on D25. Mortality, body weights, and activity levels at the udder or in the pen of pigs born to PC sows did not differ (P > 0.05) from those of piglets born to TC sows on D4 nor on D25. This study indicates that removal of confinement on the 4th-d postpartum may have had small short-term positive effects on sow behavior and stress levels (as measured by IgA), and that it did not impair piglets’ behavior and performance during lactation. Therefore, this work suggests that temporary crating limited to the first 3-d postpartum might be a feasible alternative to improve welfare under intensive production conditions. [ABSTRACT FROM AUTHOR]

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Two experiments were conducted to determine the apparent ileal digestibility (AID) of starch and gross energy (GE), the standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA), the concentration of digestible energy (DE) and metabolizable energy (ME), and the standardized total tract digestibility (STTD) of P in corn ground to 4 different particle sizes (i.e., 865, 677, 485, and 339 µm). In Experiment 1, 10 growing barrows (initial body weight: 29.2±1.4 kg) were surgically equipped with a T-cannula in the distal ileum and randomly allotted to a replicated 5×5 Latin square design with 5 diets and 5 periods in each square. One lot of corn was divided into 4 batches that were ground to the specified particle sizes and each batch was used in one diet that contained 965.5 g/kg corn (as-fed basis) as the only source of starch, GE, and AA. Results indicated that the AID of starch and GE was increased (linear, P <0.05) as the particle size decreased from 865 to 339 μm. With the exception of Trp, there was no impact of corn particle size on the SID of CP or any indispensable AA. In Experiment 2, 40 growing barrows (initial body weight: 22.8±2.1 kg) were placed in metabolism crates and allotted to a randomized complete block design with 4 diets and 10 replicate pigs per diet. Each diet contained one of the 4 batches of corn used in Experiment 1 (977.0 g/kg, as-fed basis) as the only source of GE and P. Results indicated that the concentration of ME was 16.02, 16.19, 16.31, and 16.60 MJ/kg dry matter for corn ground to a mean particle size of 865, 677, 485, and 339 µm, respectively. The ME concentration increased (linear and quadratic, P <0.01) as the particle size decreased. The average STTD of P in the 4 batches of corn was 37.4% and no differences among treatments were observed. In conclusion, decreasing the particle size of corn from 865 to 339 µm linearly increased the concentration of DE and ME and the AID of starch and GE in corn, but the particle size of corn did not affect the STTD of P or the SID of indispensable AA and CP. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the efficacy of Sangrovit®, a plant-derived feed additive, given throughout the nursery stage via feed at 15 ppm and 50 ppm, on the health status and performance of weaners against negative controls. In a 900-sow farrow-to-finish farm, a total of 864 piglets were divided into three groups: (i) negative controls (NC); (ii) Sang 15: same feed as NCs, plus 15 g Sangrovit® /t of feed; (iii) Sang 50: same feed as NCs plus 50 g Sangrovit® /t of feed. The results indicated that administration of 50 ppm-Sangrovit® had the most beneficial effects on growth performance in weaning pigs. Specifically there was increase of body weight and average daily gain, as well as reduction of feed conversion ratio. Blood analysis from the Sang groups and especially the Sang 50 group revealed low values of haptoglobin and serum amyloid A. [ABSTRACT FROM AUTHOR]

Highlights: [•] Safety study of CLNA in pig. [•] No change of body composition and biochemistry parameters. [•] Perturbation of PUFA balance in tissues. [Copyright &y& Elsevier]

Thousands of quantitative trait loci (QTL) have been identified for a wide range of economically important phenotypes in pigs. Recently, QTL analyses have begun to use high-density single nucleotide polymorphism (SNP) panels and applications have extended beyond experimental intercrosses to outbred populations by exploiting long-range linkage disequilibrium that results in higher resolution QTL mapping. Relevant phenotypes generally fall under categories of growth and body composition, carcass and meat quality, reproduction, and disease resistance. A few expression QTL (eQTL) studies have been performed that integrate transcriptional profiles with genotype data by considering expression levels as response variables in QTL analyses for identifying genes controlling important trait phenotypes. Rapidly evolving genomics technologies, including RNAseq, provide tremendous opportunities for QTL and eQTL discovery. In this review, we discuss recent progress in pig QTL and eQTL discovery, including approaches for allele-specific expression, and implications of these discoveries for pig breeding and genetics. [Copyright &y& Elsevier]

Abstract: Solute carrier family 27A (SLC27A) molecules play a fundamental role in the cellular uptake of long-chain fatty acids in a wide variety of tissues and organs. Although polymorphisms at the pig SLC27A1 and SLC27A4 genes have been associated with backfat thickness in pigs, the existence of associations with lipid composition traits has not been investigated yet. Herewith, we have sequenced the coding regions of the SLC27A1, SLC27A2 and SLC27A4 genes in 15 Duroc pigs, revealing the existence of three single nucleotide polymorphisms (SNP) at SLC27A1 (c.441C>T, c.747A>G and c.⁎400C>T) and two additional SNP at SLC27A4 (c.243T>G and c.837C>T). The performance of an association analysis with a wide array of serum and muscle lipid traits revealed the existence of suggestive associations (nominal P-value <0.05, but not significant after correction for multiple testing) between SLC27A1 genotype and gluteus medius saturated fatty acid (SFA) and stearic contents (%), and between SLC27A4 genotype and gluteus medius SFA content (%). Similarly, SLC27A1 genotype was suggestively associated with SFA content (%) at the longisimus thoracis et lumborum muscle. These findings agree from a functional point of view with the essential role of SLC27A family members in cellular fatty acid uptake and reinforce the need of further exploring the role of these molecules in defining muscle lipid composition. [Copyright &y& Elsevier]

Previous selection experiments using residual feed intake (RFI) to select pigs with a high feed efficiency have reported that a low RFI was associated with a reduced body fat content and a greater muscle glycogen content. In the current study, growing Large White female piglets from 2 lines divergently selected for RFI were used to determine the changes in energy and protein metabolisms in key tissues and their cross talks in response to selection. Pigs of low RFI (RFI-; n = 26) or high RFI (RFI+; n = 36) selection lines were offered free access to feed during postweaning and growing periods. Pigs of each line were then slaughtered at 19 kg (n = 8 per line) or 115 kg BW (n = 14 to 18 per line). A third group of pigs of the RFI+ line was offered feed at the same level per metabolic BW (BW0.60) as RFI- pigs (group RFI+R, n = 14). Regardless of the growth period considered, G:F was less in RFI+ pigs than in RFI" pigs. At 19 kg BW, RFI+ and RFI" pigs had a similar body composition and tissue lipid content. The fractional rate of protein synthesis and proteasome activity were decreased {P < 0.090) in the livers of RFI+ pigs compared with RFI" pigs whereas activities of energy catabolic enzymes did not differ in the liver and LM samples. Plasma insulin was conversely greater (P = 0.049) in RFI+ pigs at this stage. At 115 kg BW, enzyme activities of protein catabolism in the liver and in the LM did not differ (P> 0.10) between RFI+ pigs and RFI" pigs. Both lactate dehydrogenase activity participating in glucose metabolism and hydroxylacyl-CoA dehydrogenase activity involved in fatty acid oxidation were greater (P < 0.05) in the liver and LM of RFI+ pigs compared with RFI" pigs. In the liver, contrary to the LM, those differences in enzyme activities were directly associated with selection on RFI regardless of ADFI. Increased backfat depth and content and greater lipid content and adipocyte hypertrophy (P < 0.05) in subcutaneous adipose tissue were reported in RFI+ pigs compared with RFI" pigs at 115 kg B W without marked changes in key lipogenic enzyme activities; these changes were directly associated with ADFI. In conclusion, the present study shows an increase of catabolic pathway activities in the liver and muscle of RFI+ pigs at market weight that is likely to generate more ATP compared with RFI" pigs. [ABSTRACT FROM AUTHOR]

The unprecedented increase in litter size over the last decade has led to a perceived increase in the number of fallback pigs (Sus scrofa). However, there is little peer-reviewed data available regarding the biological differences between fallback pigs and their normal cohorts. Therefore, the objective of this experiment was to identify differences in the biology and physiology, and thus the growth and metabolism, between pigs with varying weaning weights (WW) and postweaning performance. To accomplish this objective, a total of 120 barrows (PIC C22/C29 * 337) were used in growth and comparative slaughter experiments. Pigs were selected from a population of 960 weanling pigs to represent the 10% lightest, median, and heaviest pigs at weaning (n = 40 pigs per WW category). Eight pigs from each WW category were harvested on d 5 postweaning as the initial slaughter group (ISG). The remaining 96 barrows were housed in individual crates, fed ad libitum quantities of a common diet during a 27-d growth study, and were harvested on d 33 or 34 postweaning. After the completion of the live animal component of the experiment, pigs within each WW category were further stratified into the slowest, median, or fastest 33% ADG categories. This resulted in a total of 9 treatments in a nested design. Fallback pigs were designated as those belonging to the slowest ADG category from either the lightest or median WW categories. Data were analyzed using the GLIMMIX procedure of SAS with the fixed effects of WW category and WW(ADG). Although feed intake was maximized (P < 0.0001) by WW(ADG) category, feed efficiency was not different (P = 0.30). When equalized per unit of BW, WW(ADG) category greatly affected (P < 0.02) eviscerated carcass, organ, and metabolic BW, but not (P = 0.28) empty BW. There were no differences (P > 0.12) in tissue nutrient concentrations, ratios, or energy content among pigs in the growth experiment. All tissue deposition rates, which were calculated as the difference between tissue nutrient concentrations of the growth experiment and initial slaughter groups, were maximized (P < 0.0002) by WW(ADG), even when equalized per unit of B W. In conclusion, WW and ADG affect tissue accretion rates, but not feed efficiency or carcass composition in nursery pigs. [ABSTRACT FROM AUTHOR]

A pure form of salbutamol has the poten-tial to deliver positive production benefits to the swine industry. The aim of this experiment was to determine the effects of salbutamol on growth, carcass measures, and health of finishing pigs. The study used 192 pigs (89 ± 1 kg BW) housed in groups of 6 in 32 pens and assigned to 1 of 4 treatments: 1) control (CTL), 0 mg/kg salbutamol; 2) 2R, control diet with 2 mg/kg of the pure R-enantiomer of salbutamol; 3) 4R, control diet with 4 mg/kg of pure R-salbutamol; or 4) 8RS, control diet with 8 mg/kg of a 50:50 mixture of the R- and S-enan-tiomers. All diets were offered ad libitum for 4 wk. All pigs were weighed and pen feed intakes were recorded weekly. At slaughter, individual HCW and measure-ments of the lOth-rib loin muscle area (LMA), color, marbling, firmness, and back fat, last lumbar, and mid-line back fat depths were collected. Data were analyzed using Proc GLM of SAS, with pen as the experimental unit. Overall, 2R and 4R pigs had greater ADG than CTL pigs (P < 0.05) and, at slaughter, were heavier than CTL pigs (P < 0.01). Overall, 8RS pigs had decreased ADFI {P < 0.05), and CTL pigs had poorer G:F (P < 0.001) than the other 3 treatments. All salbutamol-fed pigs had 5 to 6 kg greater HCW (P < 0.001), 2% to 3% increased carcass yield (P < 0.001), 5.6 cm2 larger LMA CP < 0.01), 3 to 4 mm less lOth-rib back fat (P < 0.01), and 2 mm less lumbar back fat (P < 0.05) than CTL pigs. However, control pigs had greater loin muscle color scores (P < 0.05) and marbling scores (P < 0.001) than all salbutamol-treated pigs. Taken together, these data indicate that as little as 2 mg/kg R-salbutamol has a positive effect on pig growth and carcass composition. However, the effects of salbutamol on meat quality re-quire further research. [ABSTRACT FROM AUTHOR]

Ninety hybrid (mainly Large White × Landrace) pigs from 2 experimental replicates were used to study the potential use of computed tomography (CT) as a nondestructive technology for estimating the chemical body composition of growing pigs. Body tissue components (lean, fat, and bone) of 6 live pigs from each sex (boars, gilts, and barrows) were assessed by CT imaging before slaughter at approximately 30, 60, 90, 120, and 150 kg of BW. After slaughter, the empty body components were ground and frozen until analyzed for protein, lipid, ash, and moisture content. Several growth functions were evaluated and the allometric function (Y = aBWb), which was evaluated as log10chemical component weight = b0 + b1log10BW, provided the best fit to the data. For each sex, the allometric coefficient (b1) for protein (0.92 to 0.99) was close to but less than 1; for ash (1.03 to 1.12), it was close to but greater than 1; for moisture (0.82 to 0.86), it was less than 1, and for lipid (1.61 to 1.71), it was greater than 1. Deposition rates (change in component weight per unit change in BW) for each chemical component were predicted using derivatives of the function. The mean deposition rates for protein and lipid were 0.141 and 0.286 kg/kg of BW gain, respectively. The deposition rate for protein was generally stable across different BW, whereas that for lipid increased as BW increased. In addition, linear, quadratic, exponential, and logistic functions were fitted to the data to study the relationship between the CT data and chemical components. The linear function was assessed to be the best equation, based on the Bayesian information criterion. The prediction equation for protein (kg) = -1.64 + 0.28 × CT lean (kg), and for lipid (kg) = -0.69 + 1.09 × CT fat (kg), had R2 values of 0.924 and 0.987, respectively. Sex had no effect (P > 0.05) on the prediction of protein and lipid. The effect of BW was not significant (P > 0.05) for the prediction of lipid, but it was significant (P > 0 0.05) for the prediction of protein. However, the addition of BW to the base prediction equation for protein resulted in an increase of only 0.013 in the R2 value. It was concluded from this study that CT scanning has great potential as a nondestructive technology for estimating the physical and chemical body composition of pigs. Additional research is required to validate the utility and accuracy of the prediction equations. [ABSTRACT FROM AUTHOR]

Abstract: Data were collected in the frame of the French pig breeding scheme for the Piétrain breed in which the halothane sensitivity allele (n) is segregating. This data set was used to estimate: (1) genetic parameters for residual feed intake (RFI) and growth, body composition and meat quality traits and (2) effect of the three halothane genotypes on these traits. Individual feed intake of animals raised from 35 to 107kg body weight in collective pens (12 animals maximum) was recorded using single-place electronic feeders. A total of 2312 animals were tested between 2002 and 2009 in three French central test stations: 176 were homozygous non-sensitive (NN), 470 were heterozygous (Nn) and 1666 were homozygous sensitive (nn) for the halothane locus. Variance components were estimated using the REML methodology applied to a multitrait animal model, including a random litter effect and, for meat quality traits, a random slaughter day effect. RFI showed a moderate heritability (0.40±0.06), similar to the estimate for feed conversion ratio (FCR, 0.47±0.07), with a genetic correlation of 0.85±0.04 between these traits. Pairwise contrasts between halothane genotypes showed that the halothane genotype did not affect RFI, contrary to FCR (P<0.01 for all pairwise contrasts). We conclude that, in the Piétrain breed, improving feed efficiency by selecting for lower RFI would improve FCR and reduce daily feed intake with limited impacts on growth rate and carcass traits. Moreover, it is not expected to modify the frequencies of the halothane alleles in the population, contrary to selection for reduced FCR. [Copyright &y& Elsevier]

Abstract: Numerous quantitative trait loci (QTL) have been identified for growth and feed intake in pigs, however, there are currently no reports of interactions between QTL (epistasis) for these traits at different stages of growth. A genomic scan for epistatic QTL was conducted on animals from a three generation full-sib population, created by crossing Pietrain sires with a crossbred dam line. All types of two-locus interactions were fitted in the model using Cockerham''s decomposition, by regressing on a linear combination of the individual QTL origin probabilities. This study is the first to report epistatic QTL for growth, feed intake and chemical body composition in pigs. Eighteen significant epistatic QTL pairs were identified, seven affecting growth, six affecting feed intake or food conversion ratio, and five affecting chemical body composition. Most interacting QTL resided on different chromosomes; only two were located on the same chromosome. The identified QTL pairs explained substantial proportions of the phenotypic variance, from 5% to 10.3%. All types of digenic epistatic effects were identified with the additive-by-additive effect being the most prevalent. These findings suggest that epistasis is important in the genomic regulation of growth, feed intake and chemical body composition. Furthermore, interactions occur between different pairs of epistatic QTL for the same trait depending on the growth stage, increasing the complexity of genomic networks. This agrees with studies on gene expression levels which showed that those are time and tissue dependent. [Copyright &y& Elsevier]

Abstract: Dietary fatty acid composition has been shown to influence fat deposition in rodents, chickens and pigs. Results in pigs, however, have been less clear than in other species and may relate to the level of fat/oil added to the diet and the reporting of gross carcass composition instead of gravimetrically measured fat content. The objectives of the experiment were to study the effect of dietary fat composition on whole pig (carcass+viscera) fatty acid (FA) composition and to perform a whole-body balance in order to study de novo FA synthesis and the fate of essential FA. Seventy crossbred gilts (61.8±5.2kg BW) were divided into 10 animals per treatment. Pigs were fed one of seven treatments: a semi-synthetic diet formulated to contain a very low level of fat (NF) and six fat supplemented diets (10%) based on a barley–soybean meal. The supplemental fats were tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), blend (FB) (55% tallow, 35% sunflower oil, and 10% linseed oil) and fish oil blend (FO) (40% fish oil and 60% linseed oil). In addition, 5 pigs were killed at 61.8kg to measure body composition at the start of the balance period. Carcass and viscera fat content and FA composition were determined to perform a balance in pigs growing from 61.8 to approximately 100kg BW. Whole-body FA composition reflected dietary treatments; viscera showed a high content of long-chain polyunsaturated fatty acids. Whole-body fat content of HOSF (26.7%) and SFO (26.7%) fed animals was higher than T (22.9%) fed animals (P <0.05). The ratio of de novo FA synthesis (endogenous FA) of pigs fed the very low fat diet was 1.6:1.0:3.0 for palmitic, stearic and oleic acids, respectively. The different diets containing high amounts of polyunsaturated FA (SFO, LO and FO) showed deposition ratios (not catabolizated exogenous FA) of linoleic and linolenic acids between 64.8 and 66.5, and 62.9 and 64.1%, respectively, whereas deposition rates of arachidonic, eicosapentaenoic and docosahexaenoic acids were 33.6, 47.9 and 48.9%, respectively. Tissue content of eicosapentaenoic acid and arachidonic acid increased in the diets containing high levels of linolenic and linoleic acids (P <0.05), respectively, but the diet containing high linolenic acid did not increase docosahexaenoic acid deposition (P <0.05). In conclusion, dietary tallow lowers whole animal fat content as compared to sunflower oil and high-oleic sunflower oil diets. [Copyright &y& Elsevier]

Experiments carried out to determine the amino acid requirement in growing animals are often based on the premise that the amino acid composition of body protein is constant. However, there are indications that this assumption may not be correct. The objective of this study was to test the effect of feeding piglets a diet deficient or not in total sulfur amino acids (TSAA; Met1Cys) on nitrogen retention and amino acid composition of proteins in different body compartments. Six blocks of three pigs each were used in a combined comparative slaughter and nitrogen balance study. One piglet in each block was slaughtered at 42 days of age, whereas the other piglets received a diet deficient or not in TSAA for 19 days and were slaughtered thereafter. Two diets were formulated to provide either 0.20% Met and 0.45% TSAA (on a standardized ileal digestible basis) or 0.46% Met and 0.70% TSAA. Diets were offered approximately 25% below ad libitum intake. At slaughter, the whole animal was divided into carcass, blood, intestines, liver, and the combined head, tail, feet and other organs (HFTO), which were analyzed for nitrogen and amino acid contents. Samples of the longissimus muscle (LM) were analyzed for myosin heavy chain (MyHC) and actin contents. Nitrogen retention was 20% lower in piglets receiving the TSAA-deficient diet (P<0.01). In these piglets, the nitrogen content in tissue gain was lower in the empty body, carcass, LM and blood (P<0.05) or tended to be lower in HFTO (P<0.10), but was not different in the intestines and liver. The Met content in retained protein was lower in the empty body, LM and blood (P<0.05), and tended to be lower in the carcass (P<0.10). The Cys content was lower in LM, but higher in blood of piglets receiving the TSAA-deficient diet (P<0.05). Skeletal muscle appeared to be affected most by the TSAA deficiency. In LM, the Met content in retained protein was reduced by 12% and total Met retention by more than 60%. The MyHC and actin contents in LM were not affected by the TSAA content of the diet. These results show that a deficient TSAA supply affects the amino acid composition of different body proteins. This questions the use of a constant ideal amino acid profile to express dietary amino acid requirements, but also illustrates the plasticity of the animal to cope with nutritional challenges. [ABSTRACT FROM AUTHOR]

The objective of this work was to determine if pigs of similar BW, but differing in 10th–rib hackfat thickness, would differ in their selection of dietary protein. The first experiment was conducted with guts and was designed in a 2 x 2 factorial arrangement with the main effects of body fat (lean vs. fat) and feeding program (single vs. choice). Crossbred guts (n = 32) with an initial BW of 79 kg were sorted into high (2.24 cm, fat) and low backfat (1.51 cm, lean; P < 0.001) groups based on real–time ultrasound scans at the 10th rib. Diets were 1) a low–protein corn–based diet supplemented with crystalline AA (8.5% CP, 0.58% Lys) and 2) a high–protein cornand soybean meal–based diet (22.7% CP, 1.275% Lys). During wk 1, all pigs were fed a 50:50 mix of the low–protein and high–protein diets. From d 7 to 28, one–half the pigs in the lean and fat groups were given a choice of lowand high–protein diets in separate feeders, whereas the others remained on the 50:50 mix. Initial differences in 10th–rib backfat thickness were maintained through d 28 (fat, 3.02 cm; lean, 2.42 cm; P < 0.001). Circulating leptin concentrations were greater in the fat pigs than in the lean pigs (3.84 vs. 3.35 ng/mL; P < 0.05). Average daily gain (1.06 kg/d) and ADFI (2.64 kg/d) were not different between treatment groups. However, the pattern of selection was different in the choice groups such that lean pigs consumed more (64.4%) of the high–protein diet than did fat pigs (35.6%, P < 0.01), resulting in a difference in the percentage of protein consumed (lean 16.9% CP; fat = 12.8% CP; P < 0.01). A second experiment of similar design, but with barrows (n = 32; initial BW 69 kg), was conducted. Barrows classified as fat had 2.33 cm of 10th–rib backfat as compared with 1.75 cm in the lean group (P < 0.01). The percentage of protein in the diet selected by the fat barrows was not different from that selected by the lean barrows (15.9 vs. 17.4%). The lack of difference in selection pattern in barrows may be accounted for by the relatively smaller difference in body composition between the fat and lean classifications in the barrows in the choice feeding program as compared with body composition of the gilts. These results demonstrate that gilts of similar BW, but differing in composition, likely have different nutrient requirements and diet selection patterns. Although allowing pigs to self–select did not alter growth rate, the results indicated that diet selection can be used to allow pigs to meet their individual nutrient requirements more closely. [ABSTRACT FROM AUTHOR]

The objective of this work was to determine if pigs of similar BW, but differing in 10th–rib hackfat thickness, would differ in their selection of dietary protein. The first experiment was conducted with guts and was designed in a 2 x 2 factorial arrangement with the main effects of body fat (lean vs. fat) and feeding program (single vs. choice). Crossbred guts (n = 32) with an initial BW of 79 kg were sorted into high (2.24 cm, fat) and low backfat (1.51 cm, lean; P < 0.001) groups based on real–time ultrasound scans at the 10th rib. Diets were 1) a low–protein corn–based diet supplemented with crystalline AA (8.5% CP, 0.58% Lys) and 2) a high–protein cornand soybean meal–based diet (22.7% CP, 1.275% Lys). During wk 1, all pigs were fed a 50:50 mix of the low–protein and high–protein diets. From d 7 to 28, one–half the pigs in the lean and fat groups were given a choice of lowand high–protein diets in separate feeders, whereas the others remained on the 50:50 mix. Initial differences in 10th–rib backfat thickness were maintained through d 28 (fat, 3.02 cm; lean, 2.42 cm; P < 0.001). Circulating leptin concentrations were greater in the fat pigs than in the lean pigs (3.84 vs. 3.35 ng/mL; P < 0.05). Average daily gain (1.06 kg/d) and ADFI (2.64 kg/d) were not different between treatment groups. However, the pattern of selection was different in the choice groups such that lean pigs consumed more (64.4%) of the high–protein diet than did fat pigs (35.6%, P < 0.01), resulting in a difference in the percentage of protein consumed (lean 16.9% CP; fat = 12.8% CP; P < 0.01). A second experiment of similar design, but with barrows (n = 32; initial BW 69 kg), was conducted. Barrows classified as fat had 2.33 cm of 10th–rib backfat as compared with 1.75 cm in the lean group (P < 0.01). The percentage of protein in the diet selected by the fat barrows was not different from that selected by the lean barrows (15.9 vs. 17.4%). The lack of difference in selection pattern in barrows may be accounted for by the relatively smaller difference in body composition between the fat and lean classifications in the barrows in the choice feeding program as compared with body composition of the gilts. These results demonstrate that gilts of similar BW, but differing in composition, likely have different nutrient requirements and diet selection patterns. Although allowing pigs to self–select did not alter growth rate, the results indicated that diet selection can be used to allow pigs to meet their individual nutrient requirements more closely. [ABSTRACT FROM AUTHOR]

A study was conducted to appraise a new EchoMRI™ device for body composition analysis (BCA) of infants and to compare it with dual energy X-ray absorptiometry (DXA), using chemical analysis as a reference method. The calibration part of the study included cross-validation comparisons between EchoMRI™ measurements of awake, anesthetized and dead piglets of the calibration set. It also included comparison of two different approaches to refining the calibration of EchoMRI™, by low- or by high-dimensional linear regressions. Only the low-dimensional approach was applied to DXA. The validation part yielded EchoMRI™ accuracy of 27 g and 70 g for fat and total water, respectively, on piglets scanned while anesthetized, as compared with 24 g and 57 g, respectively, for DXA. EchoMRI™ precision was found to be 4 g and 7 g for fat and total water, respectively, for anesthetized piglets, as compared to 16 g and 14 g, respectively, for DXA. The differences between fat measurements of awake, anesthetized and dead piglets can be statistically significant, but are comparable in magnitude to random errors. To summarize: Characterization of random errors by CV, especially that of fat, is not suitable for BCA, whereas absolute errors or errors relative to total body weight can be applicable. Low- and high-dimensional regressions offer nearly the same accuracy improvements. Improved DXA and EchoMRI™ offer nearly the same accuracy, within 1% of weight in fat, while EchoMRI™ has better precision, within 0.2 % of weight in fat for anesthetized and dead piglets as compared to DXA's 0.5-0.6% [ABSTRACT FROM AUTHOR]

This study was performed to assess the effects of potato protein and fish protein on concentrations of lipids in plasma and lipoproteins and the expression of genes involved in lipid metabolism in pigs used as an animal model. Therefore, 27 young male pigs with an average body weight of 22 kg were fed diets supplemented with protein extracted from potatoes (containing 849 g protein/kg dry matter), Alaska Pollack fillet as a source of fish protein (containing 926 g crude protein/kg dry matter) or casein which was used as control, for 3 weeks. Diets were formulated to supply identical amounts of each protein to the pigs by the three protein sources, namely 116 g/day in first week and 150 g/day in the second and third week. Pigs fed potato protein had lower concentrations of cholesterol in plasma and LDL than pigs fed casein (p < 0.05); no effect was observed on concentrations of HDL cholesterol and triglycerides. Pigs fed fish protein had lower cholesterol concentrations in plasma, LDL and HDL, and lower triglyceride concentrations in triglyceride-rich lipoproteins than pigs fed casein (p < 0.05). mRNA concentrations of genes involved in bile acid synthesis and cholesterol uptake were higher in pigs fed fish protein than in pigs fed casein (p < 0.05); no effect on these genes was observed in pigs fed potato protein. Expression of genes involved in lipogenesis and fatty acid oxidation was not altered by fish protein. In conclusion, this study shows that fish protein and potato protein lower plasma cholesterol concentrations in pigs. The hypocholesterolaemic effect of fish protein might be in part caused by a stimulation of bile acid synthesis; the reason for the hypocholesterolaemic effect of potato protein requires further elucidation. [ABSTRACT FROM AUTHOR]

The objective was to investigate the effect of supplementing a wheat distillers dried grains with solubles (wheat DDGS)-based diet with carbohydrase enzyme blends on growth performance and nutrient digestibilities in growing and finishing pigs. In Exp. 1, 48 pigs with a BW of 36.5 ± 1.03 kg (mean ± SD) were randomly assigned to 24 pens (2 pigs per pen) on the basis of sex and BW, and pigs were randomly allocated to experimental diets (6 pens per diet). Dietary treatments were a positive control (PC) formulated to meet or exceed NRC (1998) nutrient requirements and a negative control (NC) with DE and Lys reduced by 4 and 5%, respectively, from the PC diet and fed without or with an enzyme blend at 2 levels. Level 1 enzyme supplied 2,600 U of xylanase, 1,200 U of β-glucanase, and 1,300 U of cellulase per kg of diet; level 2 enzyme provided twice the activities for each enzyme in level 1 per kilogram of diet. Chromic oxide was used as an indigestible marker. Pigs fed the NC diet had less (P < 0.05) ADG than those fed the PC diet. Supplementing the NC diet with enzyme blends linearly increased ADG (P < 0.01). The ADFI was not affected by dietary treatment. The PC diet had greater (P = 0.04) G:F compared with the NC diet, but not the enzyme-supplemented diets. Pigs fed the PC diet had greater (P < 0.01) digestibilities of N, GE, and ether extract compared with those fed the NC diet. Addition of level 2 enzyme to the NC diet improved (P < 0.05) digestibilities of DM, N, GE, and ether extract to levels similar (P > 0.05) to those fed the PC diet. In Exp. 2, 4 ileal cannulated barrows (80.8 kg of BW; SD = 0.65) were allotted to 4 diets in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Experimental diets contained 15 or 30% wheat DDGS and were fed without or with enzyme addition. The enzyme supplement supplied 2,200 U of xylanase, 1,100 U of β-glucanase, and 1,200 U of cellulase per kg of diet. Apparent ileal digestibilities (AID) of DM, OM, and energy in enzyme-supplemented diets were greater (P < 0.05) than in unsupplemented diets. There was an interaction effect (P < 0.05) of wheat DDGS inclusion level and enzyme supplementation on AID of DM and Ser. Enzyme supplementation improved (P < 0.05) AID of DM in the diet with 30% wheat DDGS but not 15% wheat DDGS. The results shows that multienzyme supplementation of 30% wheat DDGS-based diet improved growth performance and apparent total tract digestibility of DM, N, GE, and crude fiber in growing pigs and AID of nutrients in finishing pigs. [ABSTRACT FROM AUTHOR]

Two genetic lines of barrows and gilt pigs with lean BW gain averages of 280 and 375 g/d were used to evaluate their macro- and micromineral contents at BW intervals from 20 to 125 kg of BW. The experiment was a 2 × 2 × 5 factorial arrangement of treatments (i.e., 2 sexes, 2 genetic lines, and 5 BW intervals) conducted in a completely randomized design in 6 replicates using a total of 120 pigs. Initially, 12 pigs (3 from each generic line and sex) were killed, and then at approximately 25 kg of BW intervals to 125 kg. Pigs were fed vitamin and mineral fortified corn-soybean meal diets. At slaughter the total body (except digesta and blood) of each pig was ground and analyzed for their macro- and micromineral contents. The high-lean genetic line (P <0.03) pigs and barrows (P < 0.01) reached their targeted BW an average 3 d earlier than the low-lean genetic line and guts. Total macro- and micromineral contents increased as BW increased, generally in a linear on' quadratic (P < 0.01) manner. There was an increasing difference between genetic lines in some minerals as BW increased. Total body Ca content was greater in the low-lean genetic line with increasing differences occurring as BW increased resulting in a BW × genetic line interaction (P < 0.05), whereas P was similar for both genetic lines. The quantity of K (P < 0.01) and S (P < 0.01) increased at a greater rate in the high-lean genetic line as BW increased, resulting in BW × genetic line interactions (P < 0.01). Body Cl (P < 0.01), Mg (P < 0.06), Mn (P < 0.05), Se (P < 0.01), and Zn (P < 0.01) were greater in the high-lean genetic. As BW increased, the Ca:P and the P:K ratios were increasingly greater (P < 0.01) in the low-lean genetic line, whereas the K:Na ratio was greater (P < 0.01) in high-lean genetic line. Although K and Fe were greater (P < 0.05) in gilts than in barrows, other mineral content differences were not significant. When minerals were expressed on a per kilogram of empty BW basis, the macro- and microminerals differed (P < 0.01) as BW increased indicating a response by body maturity. Genetic line had a greater effect on mineral content per kilogram of empty BW than sex. These results indicate that differences in mineral content are largely affected by BW or physiological age and by genetic line. Best-fitting equations were developed to determine macro- and micromineral contents of both genetic lines. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine AA digestibility and the concentration of DE and ME in 5 sources of soybean meal (SBM). The 5 sources included hexane-extracted SBM produced from high-protein soybeans (SBM-HP) and conventional soybeans (SBM-CONV), and mechanically extruded-expelled SBM produced from high-protein soybeans (EE-SBM-HP), low-oligosaccharide soybeans (EE-SBM-LO), and conventional soybeans (EE-SBM-CONV). Five diets that each contained 1 source of SBM and a N-free diet were used in Exp. 1 to determine AA digestibility in each meal. Twelve glowing barrows (initial BW: 67.7 ± 1.34 kg) were allotted to a replicated 6 × 6 Latin square design with 6 periods and 6 diets in each square. Each period lasted 7 d, and ileal digesta were collected on d 6 and 7 of each period. Results of the experiment showed that the standardized ileal digestibility (SID) of all AA except Trp was similar for SBM-HP and SBM-CONV, but EE-SBM-HP and EE-SBM-LO had greater (P < 0.05) SID of His, Ile, Lys, Thr, and Val than EE-SBM-CONV. The SID of all indispensable AA in EE-SBM-HP was greater (P < 0.05) than in SBM-HP. The SID of Arg, Ile, Leu, and Phe in EE-SBM-CONV was greater (P < 0.05) than in SBM-CONV, but the SID of Trp was also greater (P < 0.05) in SBM-CONV than in EE-SBM-CONV. Experiment 2 was conducted to measure DE and ME in the same 5 sources of SBM as used in Exp. 1. Forty-eight growing barrows (initial BW: 38.6 ± 3.46 kg) were placed in metabolism cages and randomly allotted to 6 diets with 8 replicates per diet. A corn-based diet and 5 diets based on a mixture of corn and each source of SBM were formulated. Urine and feces were collected during a 5-d collection period, and values for DE and ME in each source of SBM were calculated using the difference procedure. Results showed that the ME in SBM-HP tended to be greater (P= 0.10) than in SBM-CONV (4,074 vs. 3,672 kcal/kg of DM). The ME in EE-SBM-HP also tended to be greater (P = 0.10) than in EE-SBM-CONV and in EE-SBM-LO (4,069 VS: 3,620 and 3,721 kcal/kg of DM), but there was no difference in ME between extracted and extruded-expelled meals. It is concluded that SBM-HP has a greater feeding value than SBM- CONV because of greater, concentrations of digestible AA and ME. Likewise, EE-SBM-LO has a greater concentration of most indispensable AA than EE-SBM-CONV, but the concentration of ME is similar in these 2 meals. Results of this experiment also showed that AA digestibility values in: extruded-expelled SBM are greater than in hexane-extracted SBM. [ABSTRACT FROM AUTHOR]

The deciduous dentition of the domestic pig is comprised of 28 teeth (2 × incisors ³/3 canine ¹/1, premolars ³/3 molars 0/0). The timing and sequence of deciduous dental eruption were determined from oral exams on 233 Yorkshire piglets from 0 to 5 wk of age. Eruption occurred sooner in gilts for all molariform premolars (p³, p4, and p4, P < 0.01) and first incisor, i1 (P = 0.004). Birth weight influenced eruption for all teeth except i¹ (i1, p3, p4, and p4 P < 0.01), with heavier piglets having earlier eruption. Average daily gain in wk 1 of life was associated with earlier eruption times of p³ (P = 0.006), p4 (P = 0.001), and i¹ (P = 0.001), whereas ADG during wk 2 was associated with earlier eruption for p4 (P = 0.036). The parity (P = 0.025) and age (P = 0.013) of the sow were associated with earlier eruption of i1. No litter characteristics were found to be significant. Sequence of eruption was determined to be i1, p³, p4, i¹, p3, p4, although polymorphisms (reversals) were found to occur in over 40% of individuals of both sexes for mandibular i1 and p4 and maxillary p³ and i1. Size of the left i³, which is already erupted at birth as part of the needle teeth dentition, was found to be larger in males (P = 0.026). Body weight gain was not associated with the size of i³. Eruption times of p³ and p4 (the first premolars to erupt) occurred later than previously reported in the literature. Because these teeth are associated with initiation of feeding behavior for miniature breeds, implications of molar eruption on feeding behavior and feed intake should be considered. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this work was to investigate whether the C3469T mutation at exon 3 of the pig leptin (Lep) gene is associated with fatness and if the magnitude and direction of these associations is consistent within age. Repeated measurements on body weight (BW), ultrasonic subcutaneous backfat (SB) and loin-muscle (LT) thickness, and intramuscular fat (IMF) content and composition were taken at 160, 180, 215 and 225 days of age on 162 Duroc barrows previously genotyped for the C3469T mutation. Plasma leptin concentration was determined at 180 days. A total of 505 records of IMF content and composition, which were determined both in live samples of longisimus dorsi muscle (LM) and in carcass samples of LM and gluteus medius muscle, were used in the analyses. The genotypic frequencies associated with the C3469T Lep mutation were 0.76, 0.23, and 0.01 for TT, TC, and CC genotypes, respectively. The effect of the Lep genotypes was assessed using a Bayesian approach based on a polynomial mixed model on age. No evidence was found for an association of the Lep genotypes neither with BW, SB thickness nor with plasma leptin concentration. The posterior mean of the difference TT–TC ranged, for LT, from 0.82 (160 days, posterior probability density (PP)>0 of 87%) to 1.98 mm (220 days, PP>0 of 96%) and, for IMF, from 0.96 (160 days, PP>0 of 84%) to −1.64 mg/g DM (220 days, PP>0 of 2%). The results suggest an age-dependent association of the C3469T Lep polymorphism with LT and IMF, which may be useful to explain some controversial results in the literature concerning the association of this polymorphism with IMF content. [Copyright &y& Elsevier]

A study was conducted to evaluate the extent and dynamics of whole body protein deposition (Pd) and changes in chemical and physical body composition after a period of AA intake restriction in entire male pigs with high lean-tissue growth potentials. Fifty-eight entire male pigs (initial BW 15.8 ± 0.9 kg) were allotted to 1 of 3 dietary AA levels between 15 and 38 kg of BW: control (15% above requirements), AA-15% (15% below requirements), and AA-30% (30% below requirements). Thereafter, pigs were fed diets not limiting in AA content. Throughout the experiment, pigs were scale-fed at 90% of estimated voluntary daily DE intake. Representative pigs were slaughtered at 15, 38, 53, 68, or 110 kg of BW to monitor changes in body composition. Between 15 and 38kg of BW, restriction of AA intake reduced BW gain (P < 0.01; 794, 666, and 648 g/d for control, AA-15%, and AA-30%, respectively). At 38 kg of BW, AA intake restriction increased whole body lipid (LB) content (P< 0.01; 11.3, 14.3, 17.5% of empty BW), and the LB-to-whole body protein (PB) ratio (LB/ PB; P < 0.02; 0.68, 0.88, 1.10 for control, AA-15%, and AA-30%, respectively). Relationships between PB versus whole body water and PB versus whole body ash were not affected by dietary treatments (P> 0.10). At 110 kg of BW and based on BW, PB, and LB/PB, complete compensatory growth (CG) was achieved. Body weight gain between 38 and 110 kg of BW was inversely related to previous dietary AAlevels (P< 0.01; 1,089, 1,171, and 1,185 g/d for control, AA-15%, and AA-30%, respectively). For pigs on the control diet, and based on N-balance data, Pd increased with BW, from 172 g/d at 40 kg of BW to 226 g/d at 82 kg of BW. At 40 kg of BW, Pd was greater (P < 0.05) for pigs on the AA- 15% (205 g/d) and AA-30% (191 g/d) diets than pigs on the control diet (172 g/d). These findings indicate that pigs with high lean-tissue growth potentials are more likely to express compensatory Pd and their genetically determined upper limit to Pd (PdMax) after a period of AA intake restriction. This study confirms previous findings that BW effects on PdMax are small in growing pigs between 40 and 80 kg of BW. It is suggested that CG and compensatory Pd after a period of AA intake restriction is constrained by the pig's PdMax and is driven by a target LB/PB. Combined with previous observations in our laboratory, these results suggest that CG after a period of AA intake restriction tends to occur only when pigs are within the energy-dependent phase of lean-tissue growth and not when the genetically determined upper limit to lean-tissue growth, or PdMax, determines growth performance. [ABSTRACT FROM AUTHOR]

Two genetic lines of barrows and guts with different lean growth rates were used to determine the BW and chemical composition growth from 23 to 125 kg of BW. The experiment was a 2 × 2 × 5 factorial arrangement of treatments in a completely randomized design conducted in 2 replicates. Six pigs from each sex and genetic line were killed at approximately 25-kg intervals from 23 kg to 125 kg of BW. At slaughter, tissues were collected and weighed. All components were ground and frozen until analyzed for water, protein, lipid, and ash. Serial BW data were fitted to alternative functions of day of age. Based on Akaike's information criteria values, the random effects model, BW1,t = (1 + ci)(bo + b1t + b2t2), was the best mixed model equation. The chemical component mass data were fitted to alternative functions of BW. The allometric function, chemical component mass = aBWb, provided the best fit to the data. Daily deposition rates of each chemical component were predicted by using the derivatives of the 2 functions. The overall ADG of the 2 genetic lines were not different. Barrows had 0.052 kg/d greater (P = 0.03) ADG than gilts. Allometric growth coefficients for all 4 chemical components were different (P < 0.01) for each genetic line. Allometric coefficients and predicted relative growth (g/kg of BW gain) for protein and moisture mass were greater (P < 0.01) for the high lean-gain pigs than the low lean-gain pigs. Allometric coefficients for lipid mass were smaller (P = 0.001) for the high lean-gain pigs than the low lean-gain pigs overall. Allometric coefficients and predicted relative growth rates for lipid mass were greater (P < 0.01) and for moisture and protein mass were lesser (P < 0.002) than the gilts. Compared with low lean-gain pigs, high lean-gain pigs had (1)32.8% lesser predicted daily rates of lipid deposition (200 vs. 305 ± 80 g/d), with the difference increasing from 23 to 37% from 25 to 125 kg of BW; (2) 12.3% greater daily rates of protein deposition (118.7 vs. 106.0 ± 3.3 g/d); and (3) 18.8% greater predicted daily moisture accretion rates (423 vs. 356 ± 9 g/ d). Overall, harrows had 21.3% greater lipid deposition (279 vs. 230 ± 78.2 g/d) than gilts. In this study, barrows and gilts had similar predicted daily moisture, protein, and ash accretion rates. [ABSTRACT FROM AUTHOR]

Barrows and gilts of 2 genetic lines with differing lean gain potentials (high-lean = 375 g of fat-free lean/d; low-lean = 280 g of fat-free lean/d) were used to determine tissue and organ weights and compositions from 20 to 125 kg of BW. The experiment was a 2 (genetic line) × 2 (sex) × 5 (BW) factorial arrangement of treatments in a completely randomized design conducted with 2 groups of pigs in 6 replicates (n = 120 pigs). Six pigs from each sex and genetic line were slaughtered at 20 kg of BW and at 25 kg of BW intervals to 125 kg of BW. At slaughter, the internal tissues and organs were weighed. Loin and ham muscles were dissected from the carcass and trimmed of skin and external fat, and the ham was deboned. Residuals from the loin and ham were combined with the remaining carcass. Body components were ground, and their compositions were determined. The results demonstrated that tissue weights increased (P < 0.01) as BW increased. Loin and ham muscle weights increased but at a greater rate in the high-lean line and in gilts resulting in genetic line × BW and sex × BW interactions (P < 0.01). Liver and heart expressed on a BW or a percentage of empty BW basis increased at a greater rate in the high-lean line resulting in a genetic line x BW interaction (P < 0.01). Liver and intestinal tract weights were heavier in barrows than in gilts, significant only at 45 (P < 0.05), 75 (P < 0.01), and 100 (P < 0.05) kg of BW. Loin and ham muscles from the high-lean genetic line and gilts had greater (P < 0.01) water, protein, and ash contents compared with the low-lean genetic line and barrows resulting in genetic line × BW and sex × BW interactions (P < 0.01). The remaining carcass (minus loin and ham muscles) had greater. (P < 0.01) amounts of water and protein, and less (P < 0.01) fat in the high-lean genetic line and gilts. The high-lean genetic line and gilts had more total body water, protein, and ash, but less body fat, with these differences diverging as BW increased, resulting in a genetic line x BW interaction (P < 0.01). The results indicated that liver and heart weights were greater in high-lean pigs, reflecting the greater amino acid metabolism, whereas the liver and intestinal tract weights were greater in barrow than gilts, reflecting their greater feed intakes and metabolism of total nutrients consumed. [ABSTRACT FROM AUTHOR]

Two genetic lines with different lean gains were evaluated for various body measurements and indices of lean tissue in barrows and gilts from 20 to 125 kg of BW. One genetic line was identified as the low-lean line [280 g of fat-free lean (FFL)/d], and the second line was the high-lean line (375 FFL gained/d). The experiment was conducted as a completely randomized design using a 2 × 2 × 5 factorial arrangement of treatments in 6 replicates (n = 120 pigs). The 2 genetic lines and sexes were provided ad libitum access to corn-soybean mixtures that met or exceeded their required amino acid requirements for their respective lean gain potentials. Six pigs of each sex and genetic line were slaughtered initially and at 25-kg of BW intervals to 125 kg of BW. Pigs slaughtered were measured for height, width, and length using metal calipers. Backfat and LM area were measured using real-time ultrasound, with backfat depth also measured using A-mode ultrasound technology. Longissimus muscle area and backfat thickness at the 10th rib were measured on the chilled carcass. Data was analyzed using the MIXED procedure of SAS, with the animal as the experimental unit. Shoulders (P < 0.05) and lumbars (P < 0.05) were wider in the low-lean genetic line and in barrows. Gilts and the high-lean genetic line had less backfat and greater LM areas than the low-lean genetic line. As BW increased, there was a greater increase in FFL tissue and lower backfat depths in the high-lean vs. the low-lean genetic line. This resulted in a greater divergence of measurement values as BW increased. Femur weight, length, and cortical wall thickness were greater in the high-lean genetic line, but the differences were not significant. The high-lean genetic line had a greater (P < 0.01) organic matrix content in the femur and less ash, resulting in a lower percentage of bone ash (P < 0.01). The results indicate that differences occurred phenotypically between pigs having more muscle (wider hams) or more fat (wider shoulder and lumbar). As BW increased, the high-lean pigs had an increase in lean tissue, particularly after 75 kg of BW, and less backfat and less bone mineralization, whereas the low-lean line pigs had increased backfat and greater bone mineralization. Real-time ultrasound measurements using various formulas to estimate lean tissue produced values close to those determined from carcass measurements at 100 and 125 kg of BW. [ABSTRACT FROM AUTHOR]

Abstract: The effects of dietary daidzein during late gestation on maternal performance, neonatal body composition, carcass and meat quality at market weight, and skeletal muscle cellularity were studied. Multiparous sows received a soybean-free diet (n =8, control) or the same diet supplemented with 1mg daidzein/kg body weight (n =7) daily from d 85 of gestation to parturition. Litter size, litter weight, and birth weight remained unaffected by daidzein feeding. In newborn piglets from litters >15, the proportions of muscle tissue and skin tended to be decreased (P =0.09) or increased (P =0.03), respectively, after gestational daidzein feeding. The body fat percentage was higher in response to maternal daidzein (P =0.04). Postnatal growth and carcass composition at 180d of age were not affected, however, maternal daidzein supplementation led to increases in longissimus muscle pH45 (P =0.02) and pHend (P =0.11) in pigs from large litters. The proportion of fast-twitch glycolytic fibres in semitendinosus muscle was increased (P =0.06) by maternal daidzein feeding. The results suggest that supplemental daidzein in the maternal diet during late gestation marginally affects meat quality and skeletal muscle cellularity of the progeny. [Copyright &y& Elsevier]

The objective of this study was to determine whether intermittent suckling (IS) combined with an extended lactation can reduce postweaning growth check in pigs. Three weaning regimens [conventional weaning (CW), IS with 6-h separation intervals (IS6), and IS with 12-h separation intervals (IS12)] were compared. In CW (n = 17 litters), litters had continuous access to the sow until weaning (d 21, d 0 = farrowing). In IS6 and IS12, litters were separated from the sow for 12 h/d, beginning at d 14 and lasting until weaning (d 41 to 45). Litters were with the sow from 1400 to 2000 and from 0200 to 0800 (IS6, n = 14) or between 2000 and 0800 (IS12, n = 14). Litter size was standardized within 2 d after farrowing by crossfostering, resulting in an average litter size of 10.9 ± 1.8 piglets. Piglets had ad libitum access to creep feed from d 7 onward. One week after the onset of IS (d 20), creep feed intake was increased in litters from both IS groups compared with CW litters (P < 0.05). Both IS groups consumed considerable amounts of creep feed before weaning (d 41 to 45). Total feed intake before weaning was greater (P = 0.004) in IS12 (3,808 ± 469 g/piglet) than in IS6 (2,717 ± 404 g/piglet). In comparison, CW litters consumed 18 ± 9 g/piglet before weaning (d 21). Irrespective of weaning regimen, total feed intake of litters before weaning was highly correlated with postweaning feed intake (P < 0.001). Furthermore, in all treatment groups, total preweaning feed intake was correlated with postweaning growth (P < 0.10). Irrespective of treatment, piglets suckling anterior teats grew faster than piglets suckling middle or posterior teats during the first 2 wk of lactation. Body weights at the end of the experiment (d 55) were similar among weaning regimens. Onset of IS induced a growth check in both IS groups (34% for IS12 and 22% for IS6). Only a mild growth check was observed after weaning of IS litters (14% for both IS groups). However, a serious growth check (98%) was observed after weaning of CW litters. Results of the current study indicate that IS stimulated feed intake during lactation, providing a more gradual transition to weaning. Because the IS6 regimen did not prevent the growth check after the onset of IS and is rather laborious, we suggest that IS12 might be preferable for a practical implementation of IS. [ABSTRACT FROM AUTHOR]

The relationships among BW, backfat depth, and body physical and chemical composition were evaluated in response to dietary protein and DE balance in breeding gilts from 30 kg of BW to weaning of the first litter. Large White (sire) x Landrace (dam) F1 hybrid (White; n = 75) and Landrace (sire) x (Meishan x Large White; dam) (Meishan; n = 19) hybrid gilts were received at 30 kg of BW. Five gilts were taken as the initial slaughter group at 30 kg of BW, and the remaining gilts were fed diets differing in total lysine to DE ratio, high (H) vs. low (L), from 30 kg of BW to mating (rearing), and during gestation and lactation, allowing factorial investigation of dietary treatment effects and interactions during rearing, gestation, and lactation. Gilts were slaughtered at approximately 50 and 90 kg of BW, and at mating, farrowing, and weaning. Gilts fed L diets during rearing were lighter at mating (117.9 vs. 133.6 kg of BW, P = 0.035) due to a reduction in gain (592 vs. 720 g/d, P = 0.002) and a restriction in protein accretion (83 vs. 117 g/d, P = 0.001). During rearing, lipid accretion did not differ between L- and H-fed gilts (208 vs. 198 g/d, P = 0.60), but the ratio of lipid to protein accretion was about 1.5-fold greater in L-fed gilts, where lipid mass expressed as a percentage of BW was increased at mating (26.0 vs. 21.9%, P = 0.005). Effects of L diets on lipid accretion during rearing were transient; no residual effects on body lipid mass (P > 0.17) were found at farrowing or weaning. Overall, Meishan hybrids carried greater lipid mass (P < 0.001) than White hybrid gilts. Whereas the rate of body lipid and protein accretion and body lipid and protein mass can be nutritionally influenced and can vary according to growth stage, reproductive status, and genotype, this study established that body protein mass expressed as a proportion of the lipid free empty BW remains inflexible. A value for this measure of 0.188 ± 0.0052 was found in White and Meishan hybrid gilts ranging from 28 to 203 kg of BW and 3 to 36 mm backfat depth, covering growth, pregnancy, and lactation, and offered diets differing in protein and energy balance. Body protein mass can be predicted as approximately 0.2 of the lipid free empty BW once body lipid mass is estimated accurately from physical measurements, such as backfat depth (P2, mm) and BW (kg), by regression using lipid (kg) = -8.14 (SE, 1.302) + 0.167 (SE, 0.010) BW + 0.883 (SE, 0.065) P2 (residual SD = 3.51; R² = 0.912). [ABSTRACT FROM AUTHOR]

Recently, it has been shown that supplementation of sows with L-carnitine increases their plasma concentrations of insulin-like growth factor (IGF)-I, and it has been hypothesized that this may stimulate fetal myogenesis. This study was performed to investigate whether piglets of sows supplemented with L-carnitine differ in muscle fibre characteristics, chemical body composition and postnatal growth capability from pigs of control sows. Muscle fibre characteristics and chemical body composition were determined at weaning in 21 piglets of control sows and 21 piglets of sows treated with L-carnitine with similar body weights; postnatal growth capability was determined from weaning until slaughter at a body weight of 118 kg in 80 pigs of control sows and 80 pigs of sows treated with L-carnitine which had also similar body weights at weaning. Piglets of sows supplemented with L-carnitine did not differ in number, area, diameter and type (percentages of slow twitch oxidative + fast twitch oxidative fibres, and fast twitch glycolytic fibres) of muscle fibres in m. longissimus dorsi and m. semitendinosus and in chermical body composition (concentrations of dry matter, crude protein, crude fat) from piglets of control sows. Postnatal growth capability (body weight gains, feed conversion ratio) from weaning to slaughter as well as carcass composition (carcass yield, meat thickness, fat thickness) was also not different between pigs of sows treated with L-carnitine and pigs of control sows. In conclusion, data of this study do not support the hypothesis that L-carnitine supplementation of sows during pregnancy enhances fetal muscle fibre development and increases postnatal growth capability of the offspring. [ABSTRACT FROM AUTHOR]

As part of an interdisciplinary research project, the performance response of sows and their litters to the probiotic strain Enterococcus faecium NCIMB 10415, as well as some health characteristics of the piglets, were studied. Gestating sows (n = 26) were randomly allotted into 2 groups. The probiotic was administered by dietary supplementation to 1 group of sows and their respective litters (probiotic group), whereas the second group (control group) received no probiotic supplementation. The duration of the treatment was nearly 17 wk for sows (d 90 ante partum until d 28 postpartum) and 6 wk for piglets (d 15 to 56). Body weight and feed consumption were recorded weekly. The frequency of 4 toxin and 5 adhesion genes of putative pathogenic Escherichia coli was monitored weekly (d 7 to 35) by multiplex PCR assays, and fecal consistency of weaned piglets was studied daily. Probiotic treatment of lactating sows led to an overall preweaning mortality of 16.2% compared with 22.3% in the control group (P = 0.44). Animal losses during the first 3 d of the suckling period were decreased in the probiotic group (P = 0.09). For piglets (n = 153), which were weaned at 28 d, there were no overall treatment differences in BW gain, feed intake, or feed efficiency. Probiotic supplementation, however, led to nearly a 40% reduction (P = 0.012). The actual percentage of piglets with postweaning diarrhea in the probiotic group was 21% compared with 38% in the control group (P = 0.05). The study on virulence factors of dominant fecal E. coli isolates revealed a high diversity with varying frequency and distribution of each single pathogenicity gene. The 440 isolates carried 29 different pathogenicity gene combinations as well as each of the 9 pathogenicity genes alone. Altogether, isolates with more than 2 pathogenicity genes were quite rare (⩽10%), and up until d 28 isolates without any pathogenicity gene occurred most frequently. Depending on the time of sampling, one-third or more of all isolates contained est2 or est1b as single gene or in combination with other pathogenicity genes. [ABSTRACT FROM AUTHOR]

Accurate evaluations of growth and composition traits enable better management decisions regarding genetic merit, feeding, and marketing. Sires from Duroc and Pietrain populations were used to produce crossbred pigs, which were evaluated for growth and composition traits. All parents were normal for the ryanodine receptor gene. Boars from each breed were mated to either Yorkshire or F1 Yorkshire-Landrace females with 307 offspring evaluated from birth through 26 wk of age. No significant differences between sire breeds were seen for pig BW from birth through 10 wk of age. Body weight, 10th rib backfat (BF10), last rib backfat (LRF), and loin muscle area (LMA) were serially measured at 10, 13, 16, 19, 22, 24, and 26 wk of age. At 26 wk of age, Duroc-sired progeny were heavier (143.4 vs. 132.7 kg, P < 0.001), had more BF10 (27.1 vs. 23.7 mm, P < 0.001) and LRF (21.2 vs. 19.2 mm, P < 0.001), but had similar LMA (46.4 vs. 47.1 cm²) compared with Pietrain-sired progeny. Mean feed efficiency did not differ between breed of sire in any period of the study. Duroc progeny had a greater ADG (980.1 vs. 892.3 g/d, P < 0.001) from 10 to 26 wk of age than Pietrain-sired pigs. Composition traits of fat-free total lean (FFTOLN), total fat tissue (TOFAT), empty body protein (EBPRO), and empty body lipid (EBLIPID) were calculated. Random regression animal models with polynomial regression on week on-test were fitted to BW, BF10, LRF, LMA, FFTOLN, TOFAT, EBPRO, and EBLIPID from 10 to 26 wk of age. Duroc-sired harrows tended to grow faster but with more fat tissue, and Pietrain-sired guts were slower growing but leaner, whereas Duroc-sired guts and Pietrain-sired barrows were intermediate for growth and backfat measures. Serial heritability estimates generally increased from 10 to 26 wk of age with ranges as follows: BW (0.05 to 0.39), BF1O (0.13 to 0.76), LRF (0.11 to 0.79), LMA (0.05 to 0.73), FFTOLN (0.07 to 0.16), TOFAT (0.19 to 0.45), EBPRO (0.02 to 0.55), and EBLIPID (0.12 to 0.60). Pigs sired by Duroc and Pietrain boars had similar lean tissue growth but achieved it through different mechanisms. [ABSTRACT FROM AUTHOR]

A simulation model that predicts the effect of the social, physical, and nutritional environments on pig food intake and performance was extended to deal with individual variation. The aim was to investigate the effect of between-animal variation on the performance of a population of growing pigs. Variation was generated in initial state, growth potential, and ability to cope when exposed to social "stressors" (EX). Variation in initial state is described by initial body weight (BW0), from which the chemical composition of the pig is calculated. Variation in growth potential is described by creating variation in the genetic growth descriptors. Variation in EX exists between genotypes, where it has been suggested that leaner, more modern genotype pigs tend to be less able to cope. It is expected that within a population or group that the social environment (i.e., position within the social hierarchy) also affects an individual's ability to cope. In the model, it is assumed that the larger, more dominant individuals are better able to cope when exposed to social stressors. Consequently, within a population, EX is correlated with body weight around the genotype mean. Model predictions showed that increasing the variation in BW0 and EX increased the variation in pig performance. This is an important practical consideration in commercial pig production, where the heterogeneity of the population at slaughter may affect the profitability of an enterprise. The way a stressor constrains performance determines whether the mean population response to a given stressor is the same as the average individual response. If all pigs in a group are affected at the same stressor intensity (e.g., all are either mixed or not), then the predicted average individual and mean population responses will be the same. If, however, the intensity of stressor at which performance becomes limiting differs between individuals (such as space allowance or temperature), differences between the individual and mean population responses will be predicted. Variation in the growth response of a population was determined to a greater extent by variation in EX and BW0 than by variation in growth potential, when pigs were housed in simulated conditions likely to be encountered in commercial environments. Consequently, decreasing the variation in initial body weight and improving ability of pigs to cope may be a better way of improving pig performance than selecting only for increased growth potential. [ABSTRACT FROM AUTHOR]

An Hologic QDR4500 dual energy X-ray absorptiometer (DXA) was used to measure body composition in 151 pigs ranging from 10 to 120 kg live weight. Large White×Landrace pigs of mixed sexes were selected from five different experiments to evaluate DXA accuracy within and across experiments. Values predicted by DXA including total tissue mass, fat tissue mass, lean tissue mass and bone mineral content, for the live animal, carcass and half carcass were evaluated by comparison with chemically-determined values. Relationships between chemically-determined values and measurements of weight and backfat at the P2 site were also evaluated. Chemically-determined values were strongly related with DXA-derived values, more so than with weight and P2 or a combination of both, particularly in the measurement of fat composition. In contrast to estimates derived from weight and P2, DXA-derived estimates remained accurate when between experiment variation was included. Incorporation of subregions into a whole body software analysis influenced DXA’s ability to predict fat tissue mass with the most accurate measurements achieved by placing the entire scan image in the left arm region of the regional analysis grid. These results demonstrate the efficacy of DXA as a nondestructive method for determining body composition in the live animal and carcass, and its greater accuracy than current routinely used methods. [Copyright &y& Elsevier]

A total of 32 Pie´train×(Landrace×Large White) barrows were used to test the effect of reducing the dietary crude protein (CP) level on performance and composition of gain in piglets from 12 to 27 kg. Four diets based on corn, wheat, barley and soybean meal providing 1.01 g of ileal digestible lysine per MJ of NE (net energy) were prepared. Diet 1 was formulated without free amino acids (AA), while in diets 2–4, CP level was progressively reduced and free AA were supplemented according to the ideal protein concept. The CP levels were 224, 204, 184, 169 g/kg for diets 1, 2, 3 and 4, respectively. Piglets were housed individually and had free access to feed and water. The feed intake was measured daily. At the end of the experiment, animals were slaughtered and body composition was measured. The 12 control piglets were slaughtered at the beginning of the experiment and the composition of gain (water, ash, protein lipid, AA and energy) was calculated according to the comparative slaughter technique. Feed intake was the lowest (P<0.05) with diet 1 (959 g/day) and similar for diets 2–4 (1049 g/day, on average). Nevertheless, average daily gain of the animals did not differ between treatments (666 g/day, on average). Reducing CP level resulted in a numerically reduced water consumption and urine production, but no effect on the occurrence of diarrhea was observed. The N excretion over the total experiment was reduced by 42% from diet 1 to diet 4. At identical ME (metabolizable energy) intakes (2.52 MJ/day per kg BW0.60), protein and lipid composition of gain (18.9 and 13.0 g/day per kg BW0.60, on average) were not affected by the diet. Energy gain (0.94 MJ/day per kg BW0.60) and heat production (1.58 MJ/day per kg BW0.60) were also not different between treatments. The amino acid pattern of deposited protein was not affected by dietary CP level, except that histidine deposition was significantly smaller with diets 3 and 4. These results indicate that a reduction of dietary CP level by up to 55 g/kg in association with adequate AA supplementation does not affect the level of performance and body composition of piglets and contributes to lower N excretion. [Copyright &y& Elsevier]

Previous studies have shown that piglets weaned to a liquid milk replacer (MR), rather than a typical dry diet (DD) regimen, have improved growth rates and deposit more energy as body fat. In the present study, we used this model to determine whether changes in the expression of genes linked to the regulation of adiposity were related to the accelerated fat accretion. We also determined whether the increase in body fat was sustained throughout a substantial proportion of the growth curve. At weaning (19 ± 2 days of age), 96 piglets were placed in 12 replicate pens per diet (4 pigs per pen, 2 barrows and 2 gilts), and fed a liquid MR or conventional DD regimen for 5 weeks. Thereafter, 6 barrows and 6 gilts pigs from each diet were killed for determination of whole body chemical composition (less gastrointestinal contents). The remaining pigs were assigned randomly to weight target groups (60, 85, and 110 kg), placed in individual pens, and fed a conventional dietary regimen until killed at their respective weight targets for tissue sampling and determination of whole body chemical composition. Over the 5-week period in which the MR was fed, the growth rate of the pigs consuming the MR exceeded that of the pigs fed the DD by 36% (P < .05). Fat gain in these pigs was increased to 1.8 times that of the pigs fed the DD, and percentage body fat was 45% greater (P < .05). Acetyl Co-A carboxylase (ACC) activity (per mg of adipose extract protein) was not different between the two diet groups at the conclusion of the 5-week period, or at 110 kg body weight. During the MR period, actual protein gain was increased (P < .05) 22% in the pigs fed the MR as well. By 110 kg of body weight, body fat was reduced (P < .05) by 7.7% (total fat mass) and 8.3% (percentage of body weight basis) in the pigs fed MR vs. the DD group. The expression of the peroxisome proliferator activated receptors (PPAR) α and γ was not influenced by diet or by body weight. Expression of the obese gene was independent of diet, but was greater (P < .09) in pigs at 110 kg body weight than at 60 kg. These data provide additional evidence that piglets weaned to liquid diets have greater rates of growth and deposit more body fat, but that this difference subsides quickly when a typical dry dietary regimen is imposed. Furthermore, the biochemical changes responsible for the increased adiposity are independent of changes in the expression of the obese or PPAR genes, at least at the mRNA level. [Copyright &y& Elsevier]