Evaluation of the prediction of alternative measures of pork carcass composition by three optical probes

Posted in: Meat Quality, Production by admin on August 5, 2011 | No Comments

The accuracy of 3 optical probes (HGP4 Hennessey Grading Probe, Destron-Feering PG-100 probe, and Giraldo OPTO-Electronic PG-200 probe) to predict the carcass percentage of 5 alternative measures of carcass composition (fat-tissue-free lean, lipid free soft tissue, lipid-free lean, total fat tissue, and soft tissue lipid) was evaluated on 203 barrows and gilts of 7 genetic populations. The optical probe backfat depths were more closely correlated (0.963 to 0.983) than the LM depths (r = 0.695 to 0.734). The optical probe backfat depths were related to lean percentage (r = −0.82 to −0.88), total fat tissue percentage (r = 0.84 to 0.88), and soft tissue lipid percentage (r = 0.86 to 0.87). Optical probe LM depths were weakly related (r = 0.23 to 0.34) to measures of carcass lean percentage and total fat tissue percentage (r = −0.16 to −0.26). Fat-free lean percentage was predicted with residual SD (RSD) of 3.7% for equations including lastrib midline backfat thickness, 2.4 to 2.7% for equations including optical probe backfat and LM depth, and 2.3% for ribbed carcass measurements. The RSD for the optical probe equations ranged from 2.1 to 2.4% for lipid-free soft tissue percentage and from 2.0 to 2.3% for lipid-free lean percentage. The RSD for the optical probe equations ranged from 2.9 to 3.3% for total fat tissue percentage and 2.5 to 2.8% for soft tissue lipid percentage. Quadratic and cross-product variables of optical probe fat depth, LM depth, and carcass weight were significant and reduced the RSD of the equations. Optical probe backfat and LM measurements can be used to predict alternative measures of carcass composition. The predicted relationships in fat free lean percentage to backfat depth were nearly identical for each optical probe.

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Use of crude glycerol, a biodiesel coproduct, in diets for lactating sows

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An experiment was conducted to evaluate the effect of dietary crude glycerol in lactating sow diets on sow and litter performance under heat stress conditions. Mixed parity (range = 0 to 13) sows (n = 345; 253kg of BW) were assigned randomly within gestation housing location and parity to 1 of 4 dietary treatments. Treatments consisted of a cornsoybean- based control diet (CON) and 3, 6, or 9% glycerol added at the expense of corn and soybean meal. Liquid crude glycerol was incorporated in the complete diet at the time of mixing. Dietary treatments were imposed on d 109 of gestation (2.25 kg/d) when sows were moved into farrowing rooms. Heat index during lactation in farrowing rooms exceeded 25°C for all sows. At farrowing, sows were allowed ad libitum access to feed throughout lactation. Dietary treatment tended to influence ADFI of sows (CON = 6.04 kg/d; 3% = 6.21 kg/d; 6% = 5.69 kg/d; 9% = 6.00 kg/d; pooled SE = 0.18). Up to 9% crude glycerol in the diet had no effect on sow BW and backfat loss, weaning-to-estrus interval, preweaning mortality of piglets, and ADG of piglets. Increasing dietary glycerol linearly reduced litter size at weaning (CON = 9.50; 3% = 9.60; 6% = 9.36; 9% = 9.39; pooled SE = 0.08). Daily water consumption was not affected by dietary treatment. Crude glycerol did not affect respiration rates or rectal body temperatures, indicating no efficacy in reducing heat stress of sows. Plasma glycerol concentrations increased linearly as dietary crude glycerol increased (CON = 1.21 μM; 3% = 1.69 μM; 6% = 7.21 μM; 9% = 29.04 μM; pooled SE = 1.58), but plasma glucose concentrations were not affected. Crude protein content of the milk of sows was not affected by dietary treatment. Dry matter and crude fat content of the milk of the sows tended to increase linearly (DM basis: CON = 17.84%; 3% = 18.43%; 6% = 18.98%; 9% = 18.48%; pooled SE

 = 0.34; crude fat: CON = 4.78%; 3% = 4.91%; 6% = 5.50%; 9% = 5.24%; pooled SE = 0.30), whereas milk ash concentration tended to decrease linearly with increasing dietary glycerol (CON = 0.77%; 3% = 0.79%; 6% = 0.74%; 9% = 0.74%; pooled SE = 0.02). Increasing dietary crude glycerol linearly increased lactose concentration in the milk of sows (CON = 5.16%; 3% = 5.30%; 6% = 5.43%; 9% = 5.46%; pooled SE = 0.10). Results from this study indicate that lactating sows fed diets containing up to 9% crude glycerol perform similarly to sows fed a standard corn-soybean meal diet.

For more information the full article can be found at http://jas.fass.org/

Prenatal exposure to maternal low or high protein diets induces modest changes in the adipose tissue proteome of newborn piglets

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The possibility that maternal diets during gestation could affect growth and tissue development of offspring and program their later phenotype is an emerging challenge in pig production. The objective of the current study was to investigate the effects of contrasted protein levels in diets of pregnant sows on the proteomic features of subcutaneous adipose tissue (SCAT) of the offspring at birth and its possible persistence later in age. Sows were fed control (Con), low (LP), or high protein (HP) diets throughout gestation. A subset of piglets was killed at 1 d of age for SCAT sampling. The remaining piglets were cross-fostered to nonexperimental sows during lactation. They were fed standard diets during postweaning and fattening periods until 186 d of age. Modifications in SCAT protein abundance shortly after birth were investigated by 2-dimensional gel electrophoresis followed by mass spectrometry. A total of 65 spots were found differentially expressed in SCAT of 1-d-old experimental piglets vs. Con piglets. Proteins with a greater abundance in LP piglets compared with Con piglets were involved in pathways related to glucose and fatty acid metabolisms, lipid transport, and regulation of apoptosis. Upregulation of 5 proteins representative of these biological pathways in LP group vs. Con group were further validated by Western blot analyses. Furthermore, the specific activity of the key lipogenic enzyme fatty acid synthase was found greater in SCAT of 1-d-old LP piglets than in Con piglets. The main changes evidenced in SCAT of HP piglets compared with Con animals at 1 d of age rather concerned proteins putatively involved in AA metabolism or in protein turnover. Adipose tissue contents in some proteins that had displayed a greater abundance in experimental pigs compared with Con at d 1 (e.g., transaldolase, annexin II, and apolipoprotein A4) were, however, similar in the 3 groups at d 186 of age. Enolase 1 has less abundance in LP pigs compared with Con pigs at this stage. In conclusion, the proteomics tool has allowed the identification of early changes in various molecular pathways of SCAT in response to the levels of maternal protein supply during gestation.

 For more information the full article can be found at http://jas.fass.org/

Meta-analysis of the effect of the halothane gene on 6 variables of pig meat quality and on carcass leanness

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Technological meat quality is a significant economic factor in pork production, and numerous publications have shown that it is strongly influenced both by genetic status and by rearing and slaughter conditions. The quality of meat is often described by meat pH at different times postmortem, as well as by color and drip loss, whereas carcass quality is often characterized by lean percentage. A meta-analysis of findings relating to 3,530 pigs reported in 23 publications was carried out to assess the effects of the halothane gene, sex, breed, and slaughter weight of animals on 7 selected variables: pH at 45 min postmortem, ultimate pH, reflectance (L*-value), redness (a*-value), yellowness (b*-value), drip loss, and lean percentage. Two statistical methods were used in the meta-analysis: the method of effect size and the better known random effects model. The method of effect size was associated with Markov chain Monte Carlo techniques for implementing Bayesian hierarchical models to avoid the problems of limited data and publication bias. The results of our meta-analysis showed that the halothane genotype had a significant effect on all analyzed pork quality variables. Between-study variance was evaluated with the Cochran (1954) Q-test of heterogeneity. Meta-regression was used to explain this variance, with covariates such as breed, sex, slaughter weight, and fasting duration being integrated into different regression models. The halothane gene effect was associated with the breed effect only for the following variables: L*-value, b*-value, and drip loss. Slaughter weight contributed significantly only to the explanation of differences in ultimate pH between homozygous genotypes. In response to inconsistencies reported in the literature regarding the difference between the genotypes NN and Nn, results of the meta-analysis showed that the difference between these 2 genotypes was significant for all the analyzed variables except the a*-value.

 For more information the full article can be found at http://jas.fass.org/

Effects of dietary aflatoxin on the health and performance of growing barrows

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Aflatoxins, especially aflatoxin B1 (AFB1), can be greater in dried distillers grains with solubles (DDGS) because it can be concentrated during the ethanol production process. Increased use of DDGS in swine diets could potentially lead to an increased incidence of aflatoxicosis, a disease associated with decreased feed intake, reduced BW gain, and impaired liver function. The objective of this study was to determine the effects of AFB1 on the health, performance, and serum profile of growing barrows. Ninety Duroc × Yorkshire crossbred barrows were purchased (age = 35 d; BW = 14.2 kg), allocated to 9 pens with 10 pigs per pen, and randomly assigned to receive diets containing 0 μg/kg of AFB1 (CON), 250 μg/kg of AFB1 (LO), or 500 μg/kg of AFB1 (HI) for 7, 28, or 70 d in a 3 × 3 factorial arrangement of treatments. Feed intake was measured daily, and pigs were weighed and blood samples collected weekly. Serum was analyzed for concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (BILI), and blood urea nitrogen (BUN). Both ADFI and ADG were negatively affected by AFB1 treatment. Average daily feed intake was less in HI barrows than in CON barrows from wk 5 to 10 and was less in LO barrows than in CON barrows in wk 5 and again from wk 8 to 10. Also, ADFI was less in HI barrows than LO barrows in wk 10. Decreased ADG was observed in HI barrows than in CON barrows in wk 8 and 10; no differences in ADG were noted between CON and LO barrows. There was no effect of AFB1 treatment on ALT or BILI concentrations. However, both AST and BUN were affected by AFB1 treatment. Serum AST was greater in LO barrows than CON barrows in wk 5, and serum BUN was greater in CON barrows than LO barrows in wk 3. Results from this study demonstrate that the performance and health of young growing barrows were affected by consumption of an AFB1-contaminated diet, especially when fed for a more extended period.

 For more information the full article can be found at http://jas.fass.org/

Morphology and enzymatic activity of the small intestinal mucosa of Iberian pigs as compared with a lean pig strain

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Castrated male Iberian (n = 12) and Landrace × Large White (n = 12) pigs were used to study histological structure and enzymatic activity in the small intestine at 3 points of the productive cycle (BW = 15, 50, and 115 kg). Both strains were fed the same cereal-based diets (DE = 2,799 kcal・kg−1, and CP = 15%) throughout the entire experimental period. Differences in histometrical variables (villus height, width and surface, crypt depth, villus height/ crypt depth relationship, mucosal thickness, muscular layer thickness, and number of goblet cells) were found among samples of small intestinal sections (duodenum, jejunum, and ileum) at the 3 productive stages studied. Also, differences in histometrical variables of small intestinal samples were found between Iberian and lean pigs at all productive stages, although these differences tended to disappear with age. Differences in enzymatic activities (lactase, sucrase, maltase, isomaltase, aminopeptidase, and alkaline phosphatase) of small intestinal samples were found between the different intestinal sections at all productive stages studied. Although differences in enzymatic activities of small intestinal samples were found between Iberian and lean pigs at all productive stages, values tended to equalize with pig age. We concluded that differences previously found in dietary nutritional utilization between Iberian and lean strains are likely not due to differences in intestinal absorption or hydrolytic capacity.

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Correlative responses for carcass and meat quality traits to selection for ovulation rate or prenatal survival in French Large White pigs

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Correlated effects of selection for components of litter size on carcass and meat quality traits were estimated using data from 3 lines of pigs derived from the same Large White base population. Two lines were selected for 6 generations on 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 (CON). The 3 lines were kept for a 7th generation, but without any selection. Carcass and meat quality traits were recorded on the 5th to 7th generation of the experiment. Carcass traits included dressing percentage, carcass length (LGTH), average backfat thickness (ABT), estimated lean meat content, and 8 carcass joint weight traits. Meat quality traits included pH recorded 24 h after slaughter (pH24) of LM, gluteus superficialis (GS), biceps femoris (BF), and adductor femoris (AD) muscles, as well as reflectance and water-holding capacity (WHC) of GS and BF muscles. Heritabilities of carcass and meat quality traits and their genetic correlations with OR and PS were estimated using REML methodology applied to a multiple trait animal model. Correlated responses to selection were then estimated by computing differences between OR or PS and CON lines at generations 5 to 7 using least squares and mixed model methodology. Heritability (h2) estimates were 0.08, 0.58, 0.70, and 0.74 for dressing percentage, LGTH, ABT, and lean meat content, respectively, ranged from 0.28 to 0.72 for carcass joint traits, from 0.28 to 0.45 for pH24 and reflectance measurements, and from 0.03 to 0.11 for WHC measurements. Both OR and PS had weak genetic correlations with carcass (rG = −0.09 to 0.17) and most meat quality traits. Selection for OR did not affect any carcass composition or meat quality trait. Correlated responses to selection for PS were also limited, with the exception of a decrease in pH24 of GS and BF muscles (−0.12 to −0.14 after 6 generations), in WHC of GS muscle (−18.9 s after 6 generations) and a tendency toward an increase in loin weight (0.44 kg after 6 generations).

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Genetic parameters of piglet survival and birth weight from a two generation crossbreeding experiment under outdoor conditions designed to disentangle direct and maternal effects

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Multivariate Bayesian linear-threshold models were used to estimate genetic parameters of peri- and postnatal piglet survival and individual birth weight of piglets reared under outdoor conditions. Data of 21,835 individual piglet observations were available from a 2-generation crossbreeding experiment selected for direct and maternal genetic effects of postnatal piglet survival on piglet and dam levels, respectively. In the first generation, approximately one-half of the Landrace sires used were selected for large or average breeding values of maternal genetic effects on postnatal piglet survival, whereas in the second generation the Large White sires used were selected for direct genetic effects of the same trait. Estimates of direct and maternal heritability were 0.21 and 0.15, 0.24 and 0.14, and 0.36 and 0.28 for piglet survival at birth and during the nursing period, and individual birth weight, respectively. In particular, direct heritabilities are substantially large  than those from the literature estimated for indoor reared piglets, suggesting that genetic effects of these traits are substantially greater under outdoor conditions. Direct or maternal genetic correlations between survival traits or with birth weight were small (ranging from 0.06 to 0.17), indicating that peri- and postnatal survival are genetically under rather different control, and survival was only slightly positively influenced by birth weight. There were significant negative genetic correlations between direct and maternal genetic effects within each of the analyzed traits ranging from –0.36 to –0.45, which have to be considered when selecting for piglet survival. Adjustment of traits for litter size or inclusion of genetic groups showed insignificant effects on the magnitude of the estimated genetic parameters. The magnitude of genetic parameters suggested that there is substantial potential for genetic improvement of survival traits and birth weight in direct and maternal genetic effects, especially when piglets are kept under outdoor conditions.

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Effect of temperature on thermal acclimation in growing pigs estimated using a nonlinear function

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Ninety-six Large White growing barrows were used to determine the effect of temperature on thermoregulatory responses during acclimation to increased ambient temperature. Pigs were exposed to 24°C for 10 d and thereafter to a constant temperature of 24, 28, 32, or 36°C for 20 d. The study was conducted in a climate-controlled room at the INRA experimental facilities in Guadeloupe, French West Indies. Relative humidity was kept constant at 80% throughout the experimental period. Rectal temperature, cutaneous temperature, and respiratory rate were measured [breaths per minute (bpm)] 3 times daily (0700, 1200, and 1800 h) every 2 or 3 d during the experiment. The thermal circulation index (TCI) was determined from rectal, cutaneous, and ambient temperature measurements. Changes in rectal temperature, respiratory rate, TCI, and ADFI over the duration of exposure to hot temperatures were modeled using nonlinear responses curves. Within 1 h of exposure to increased temperature, rectal temperature and respiratory rate increased by 0.46°C/d and +29.3 bpm/d, respectively, and ADFI and TCI decreased linearly by 44.7 g∙d−2∙kg−0.60 and 1.32°C/d, respectively until a first breakpoint time (td1). This point marked the end of the short-term heat acclimation phase and the beginning of the long-term heat acclimation period. The td1 value for ADFI was greater at 28°C than at 32 and 36°C (2.33 vs. 0.31 and 0.26 d, respectively), whereas td1 for the TCI increase was greater at 36°C than at 28 and 32°C (1.02 vs. 0.78 and 0.67 d, respectively). For rectal temperature and respiratory rate responses, td1 was not influenced by temperature and averaged 1.1 and 0.89 d, respectively. For respiratory rate and rectal temperature, the long-term heat acclimation period was divided in 2 phases, with a rapid decline for both variables followed by a slight decrease. These 2 phases were separated by a second threshold day (td2). For rectal temperature, td2 increased significantly with temperature (1.60 vs. 5.16 d from 28 to 36°C). After td2, the decline in rectal temperature during the exposure to thermal challenge was not influenced by temperature, suggesting that the magnitude of heat stress would affect thermoregulatory responses only at the beginning of the long-term heat acclimation period. The inclusion of random effects in the nonlinear model showed that whatever the temperature considered, interindividual variability of thermoregulatory responses would exist.

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Association analyses of candidate single nucleotide polymorphisms on reproductive traits in swine

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The ability to identify young females with superior reproduction would have a large economic impact on commercial swine production. Previous studies have discovered SNP associated with economically important traits such as litter size, growth rate, and feed intake. The objective of this study was to test for association of candidate SNP with sow prolificacy reproductive traits in gilts of a Landrace-Duroc- Yorkshire composite population. Association analyses regressed additive (A), dominant (D), and imprinting (I) SNP effects on each trait with an animal model. A carnitine palmitoyltransferase 1A SNP and a glycogen synthase 1 SNP were associated with age at puberty (AP; D = 10 d and A = 3.8 d, respectively). Four IGF2 SNP were associated with AP as well, having additive or dominant effects (3.2 to 5.8 d). Two mannosidase 2B2 SNP and 2 prolactin receptor (PRLR) SNP were also associated with AP. Solute carrier 22, subfamily member 5 SNP was weakly associated with AP (D = 3.9 d). Polymorphisms within glycogen synthase 1 and protein kinase AMP-activated, gamma 3 noncatalytic subunit had associations with ovulation rate. Estrogen receptor (ESR) 1, ESR2, PPAR γ coactivator 1, and IGFBP3 SNP were significantly associated with weaning-to-estrus interval. Two PRLR SNP were associated with total number of piglets born (A = 0.57 piglets; and D = 0.61 piglets, respectively). A SNP within PRLR was also associated with number of piglets born alive (D = 0.61). The PPAR γ coactivator 1 SNP was associated with total number of piglets born (D = 0.38 piglets) and number of piglets born alive (D = 0.53 piglets). The SNP within ESR1 (A = 0.65 piglets), ESR2 (A = −0.33 piglets), IGF2 SNP (A = −0.26 piglets), and IGFBP3 SNP (D = 0.35 piglets) were associated with number of piglets born dead. A leptin SNP was associated with mummified fetuses (D = 0.09 piglets). Many of the SNP analyzed in this study are from genes involved in regulation of metabolism, suggesting that there is an important link between physiological events associated with reproduction and energy utilization. Furthermore, these production and growth trait SNP may serve to assist in selection of young females for superior reproductive performance.

For more information the full article can be found at http://jas.fass.org/