Identify known and novel candidate genes associated with backfat thickness in Duroc pigs by large-scale genome-wide association analysis

Backfat thickness (BFT) is complex and economically important traits in the pig industry, since it reflects fat deposition and can be used to measure the carcass lean meat percentage in pigs. In this study, all 6,550 pigs were genotyped using the Geneseek Porcine 50K SNP Chip to identify SNPs related to BFT and to search for candidate genes through genome-wide association analysis in two Duroc populations. In total, 80 SNPs, including 39 significant and 41 suggestive SNPs, and 6 QTLs were identified significantly associated with the BFT. In addition, 9 candidate genes, including a proven major gene MC4R, 3 important candidate genes (RYR1, HMGA1 and NUDT3) which were previously described as related to BFT, and 5 novel candidate genes (SIRT2, NKAIN2, AMH, SORCS1 and SORCS3) were found based on their potential functional roles in BFT. The functions of candidate genes and gene set enrichment analysis indicate that most important pathways are related to energy homeostasis and adipogenesis. Finally, our data suggests that most of the candidate genes can be directly used for genetic improvement through molecular markers, except that the MC4R gene has an antagonistic effect on growth rate and carcass lean meat percentage in breeding. Our results will advance our understanding of the complex genetic architecture of BFT traits, and laid the foundation for additional genetic studies to increase carcass lean meat percentage of pig through marker-assisted selection and/or genomic selection.

Meta-analytical study of the effect of fibers in neutral detergent and acidic detergent in the diet of finishing pigs

ABSTRACT: Performance and carcass traits of finishing pigs fed diets containing different levels of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were evaluated through meta-analysis. The database was constructed using information from 24 papers, 113 treatments, and 2507 animals. Correlation and variance analyze were performed. The weight gain of the pigs showed a negative correlation (P < 0.01) with the dietary NDF content and with NDF consumption. The feed conversion ratio showed a positive correlation (P < 0.01) with the inclusion of ADF in the test ingredient and with the consumption of NDF and ADF. The backfat thickness showed a negative correlation (P < 0.05) with the NDF content in the diets. The analysis of variance showed that the performance of finishing pigs was not influenced (P > 0.05) by the inclusion of ingredients with high NDF content. Likewise, the inclusion of ingredients with high ADF content did not alter (P > 0.05) feed intake and feed conversion ratio. However, the use of ingredients with a high ADF content reduced (P < 0.05) by 4% the weight gain of the pigs. The use of ingredients with high concentrations of NDF and ADF negatively affect the weight gain and feed conversion of finishing pigs; however, the ADF-related fraction has a positive relationship with the reduction of the backfat thickness.

Effect of Changes in Dietary Net Energy Concentration on Growth Performance, Fat Deposition, Skatole Production, and Intestinal Morphology in Immunocastrated Male Pigs

Nutritional requirements of heavy immunocastrated (IM) pigs and therefore appropriate feeding strategies have not yet been determined. Thus, the effects of changes in dietary net energy (NE) content were studied in 41 IM pigs, fed ad libitum diets with low, medium, and high NE content (LNE, MNE, and HNE diets, with 8.5, 9.3, and 10.0 MJ NE/kg, respectively), from 84 days of age until slaughter at an average age of 172 days and an average body weight of 122.5 kg. In the period from 143 to 170 days of age, there was a tendency for a greater NE intake (p = 0.08) in pigs fed the HNE diet along with greater (p &lt; 0.01) backfat gain. Dietary treatment affected carcass composition, as lower backfat thickness (p = 0.01) and lower area of fat over the longissimus muscle (p = 0.05) were observed in the LNE and MNE pigs. In addition, greater lean meat content (p = 0.04) was observed in the LNE pigs. Reducing the NE of the diet by replacement of cereals and soybean meal with high-fiber ingredients resulted in lower indole production in the ascending colon (p &lt; 0.01) and greater skatole production (p &lt; 0.01) in the cecum. Greater villus area, width, height and perimeter, crypt depth, and thickness of the intestinal mucosa in the jejunum, ileum, ascending colon, and descending colon were found in the LNE group (p &lt; 0.01) than in the HNE group, while those in the MNE group was intermediate. Cell proliferation was not affected by dietary treatment (p &gt; 0.05). The present results show that a reduction in dietary NE concentration lowers lipid deposition, without affecting performance or energy efficiency in IM pigs. This technique provides an advantage in terms of improved leanness, without affecting growth rate in IM pigs after immunization, which is particularly important when the backfat thickness is a determinant of carcass value and IM pigs are fattened to higher weights (e.g., in heavy pig production) or when a longer delay between immunization and slaughter is practiced.

Backfat Thickness Does Affect the Restoration of Ovarian Activity Postpartum in Different Breeding Programs in Zebu Cattle

The backfat thickness (BFT) was used to forecast the onset of ovarian activity and predict the calf growth. Eighty Brahman cows with their calves were allocated in two groups of 40 distributed in 4 months according to the month of calving, starting in March and finishing in June. One was synchronized and inseminated at fixed time following by natural mating (TAI+NM); whilst the other only by natural mating (NM). The programs started at 60 ± 5 days postpartum and ended 60 days later. From day 30 postpartum, serial ultrasound examinations and progesterone samples were used to monitor the onset of ovarian activity. The BFT in the rump area was measured by ultrasound from 30 days postpartum and every 15 days thereafter. The weight of the calves was recorded at birth and at weaning on 160 days. The adjusted effect of BFT on ovarian activity and the calves' development was assessed by binomial logistic regression at 30, 60, 75, and 120 days postpartum. The cycling cows averaged higher BFT irrespective of breeding program (P &lt; 0.001). Also, slower changes in BFT were recorded during the follow-up at each time for all cows. However, the former had the higher BFT values from calving to the end of the study (P &lt; 0.001). At 60, 75, and 120 days, the BFT measured, at the preceding time, was the only factor predicting the commencement of cyclicity (P &lt; 0.001). The accumulative pregnancy through time was higher in TAI+NM (P = 0.003). Daily weight gain and weaning weight of the calves born in March was significantly heavier (P &lt; 0.001) than peers born in April, May, or June. The most critical element to forecast the onset of ovarian activity is the monitoring of BFT around calving regardless of the breeding program. BFT to estimate the development of the calves until weaning was unpredictable.

Relationship between energy intake and growth performance and body composition in pigs selected for low backfat thickness

Genetic selection of pigs over recent decades has sought to reduce carcass fat content to meet consumer demands for lean meat in many countries (e.g.: Australia). Due to the impacts of genetic changes, it is unknown whether the carcass fat measures are still responsive to energy intake. Thus, the present experiment aimed to quantify the relationship between tissue composition and dietary energy intake in finisher pigs selected for low carcass backfat. Intact male and female pigs (n=56 for each sex; PrimegroGenetics, Corowa, NSW, Australia) were fed seven different amounts of an amino acid adequate wheat-based diet containing 14.3 MJ digestible energy (DE)/kg to provide the following daily DE intakes- 25.8, 29.0, 32.6, 35.3, 38.5, 41.5 and 44.2 (ad libitum) MJ DE/d for males, and 25.8, 28.9, 32.0, 35.6, 38.3, 40.9 and 44.5 (ad libitum) MJ DE/d for females between 60 kg and 108 kg live weight. Body composition of anaesthetised pigs was measured using the Dual Energy X-ray Absorptiometry (DXA) method when individual pigs reached 108 kg, and protein, fat and ash deposition rates were calculated. Pigs were slaughtered on the 2nd day post-DXA scan for carcass backfat measurement. The results showed that the carcass backfat thickness (standardized at 83.7 kg carcass) increased by 0.125 mm for every MJ increase in daily DE intake in male pigs (P = 0.004; R2 = 0.130), but carcass backfat of female pigs (standardized at 85.1 kg carcass) was not responsive to daily DE intake. Whole-body fat composition and fat deposition rate increased linearly (both P &lt; 0.01) in male pigs but quadratically (both P &lt; 0.01) in female pigs in response to DE intake. Every MJ increase of daily DE intake increased the rate of daily protein deposition by 3.8 g in intact male pigs (P &lt; 0.001; R2 = 0.781) and by 2.5 g in female pigs (P &lt; 0.001; R2 = 0.643). In conclusion, the selection for low backfat thickness over the last two decades has altered the response of fat deposition and backfat thickness to energy intake, particularly in female pigs. Despite this change, the linear relationship between DE intake and protein deposition rate was maintained in these modern genetics.

Market weight, slaughter age, and yield grade to determine economic carcass traits and primal cuts yield of Hanwoo beef

ObjectiveThis study was conducted to evaluate the relationship between market weight, slaughter age, yield grade, and primal cut yield in Hanwoo. MethodsA total of 403 Hanwoo (Korean native cattle) was assessed for carcass traits such as carcass cold weight, backfat thickness, ribeye area, dressing percentage, yield index, and marbling score. The production yield of the individual major primal cuts of Hanwoo beef was also measured. FindingsCarcass cold weight, ribeye area, and backfat thickness, which affect meat quality increased with increased market weight (p<0.05). The production yield of the ten major primal cuts also increased with increased market weight (p<0.05). In terms of slaughter age, carcass cold weight, ribeye area, and backfat thickness all increased from 25 months to 28-29 months, and the production yield of all prime cuts also increased with increasing slaughter age. According to the meat yield grade, carcass cold weight and backfat thickness increased from grade A to grade C, although the ribeye area was not affected. The combined findings of the study suggest that slaughtering Hanwoo at the weight of 651-700 kg and 701-750 and age of 28.23 and 29.83 months might be desirable to achieve the best quality and quantity grade of Hanwoo beef. However, the positive correlation of carcass cold weight and backfat thickness, and the negative correlation of the yield index according to primal cuts yield indicated that it is necessary to couple the slaughtering management of cattle with improved genetic and breeding method of Hanwoo to increase the production yield of the major prime cuts of Hanwoo beef.

Probiotics or Synbiotics Addition in Bama Mini-pigs’ Diets Improves Growth Performance, Carcass Traits, and Meat Quality by Altering Plasma Metabolites and Related Gene Expression of Offspring Pigs

Background: The present study evaluated the effects of maternal probiotics or synbiotics addition on growth performance, carcass traits, meat quality, plasma metabolites, and related gene expression of their offspring pigs. Methods: A total of 64 Bama mini-pigs were used and randomly divided into the control, antibiotic, probiotics, or synbiotics groups, and fed experimental diets during pregnancy and lactation. After weaning, two piglets per litter and eight piglets per group were selected and fed a basal diet. At 65-, 95-, and 125-day-old, eight pigs per group were selected for analysis. Results: The results showed that probiotics addition increased the ADFI of pigs during the 66-95 day-old and the backfat thickness at 65- and 125-day-old, whereas synbiotics addition increased backfat thickness and decreased muscle percentage and loin-eye area at 125-day-old. In meat quality, probiotics or synbiotics addition increased cooking yield, pH 45min , and meat color, while decreased drip loss and shear force at different stages. However, maternal antibiotic addition showed an increased shear force at 125-day-old. Dietary probiotics or synbiotics addition in sow diets increased several amino acids (AA) contents in the plasma and longissimus thoracis (LT) muscle, including total AA (TAA), His, Met, Asp, Arg, and Leu, while decreased Gly, Pro, Ile, α-AAA, α-ABA, β-Ala, and γ-ABA at different stages. In the LT muscle fatty acid (FA) analysis, the contents of saturated FA (SFA; including C16:0, C17:0, and C20:0) and C18:1n9t were decreased, and the contents of C18:2n6c, MUFA (C16:1 and C20:1) and UFA were increased in the probiotics group, while the contents of SFA (C10:0, C12:0, and C14:0 at 65-day-old) were increased and the contents of C20:1 and C18:1n9t were decreased in the synbiotics group. Plasma biochemical analysis revealed that maternal probiotics or synbiotics addition decreased plasma AMM, UN, and GLU, while synbiotics addition increased plasma ALT, HDL-C, and TC at different stages. Moreover, maternal probiotics or synbiotics regulated muscle fiber-type, myogenic regulatory, and lipid metabolism-related gene expressions of offspring pigs. Conclusions: In conclusion, maternal probiotics or synbiotics addition, as a nutritional intervention strategy, improved feed intake and meat quality by altering the body's metabolism of offspring pigs and gene expressions related to meat quality.