No abstract

In the genetic improvement of livestock and poultry, residual feed intake (RFI) is an important economic trait. However, in sheep, the genetic regulatory mechanisms of RFI are unclear. In the present study, we measured the feed efficiency (FE)-related phenotypes of 137 male Hu lambs, and selected six lambs with very high (n = 3) and very low (n = 3) RFI values and analyzed their liver transcriptomes. A total of 101 differentially expressed genes were identified, of which 40 were upregulated and 61 were downregulated in the low-RFI group compared with that in the high-RFI group. The downregulated genes were mainly concentrated in immune function pathways, while the upregulated genes were mainly involved in energy metabolism pathways. Two differentially expressed genes, ADRA2A (encoding adrenoceptor alpha 2A) and RYR2 (ryanodine receptor 2), were selected as candidate genes for FE and subjected to single nucleotide polymorphism scanning and association analysis. Two synonymous mutations, ADRA2A g.1429 C > A and RYR2 g.1117 A > C, were detected, which were both significantly associated with the feed conversion rate. These findings provide a deeper understanding of the molecular mechanisms regulating FE, and reveal key genes and genetic variants that could be used to genetically improve FE in sheep.

The present study was conducted to evaluate the effects of different rearing methods and stocking densities on carcass yield and proximate composition of meat in small-sized meat ducks. A total of 555 one-day-old birds were randomly allocated to six treatment groups (three replicates per treatment, sex ratio 1/1) with a 2 × 3 factorial arrangement of two rearing methods (reared in cage or net) and three stocking densities (5 [low], 7 [medium], or 9 [high] birds/m 2 ) until day 70. Five male and five female birds from each replicate were randomly selected and processed to determine the carcass yield. Proximate composition was determined by proximate analysis using the breast and thigh muscles. There was no interaction effect between the rearing method and stocking density on carcass yield. The rearing method affected the thigh muscle rate, which was higher in the cage groups ( P < 0.05). The final BW and abdominal fat rate decreased with increasing density ( P < 0.05), whereas the thigh muscle rate increased ( P < 0.05). There were significant interaction effects ( P < 0.05) between the rearing method and stocking density on the content of protein, fat, and collagen. The content of fat and moisture was greater and lower, respectively, in the cage groups ( P < 0.05). The content of moisture, fat, and collagen with a medium density was higher ( P < 0.05). In addition, the content of protein and fat was lower in the ducks fed in nets at low and high densities ( P < 0.05), respectively; the collagen content of breast and thigh muscle was lower in the ducks fed in cages and nets, respectively, at a low density ( P < 0.05). Our findings provide valuable insights into the single and interactive effects of the rearing method and stocking density on duck slaughter performance and proximate composition of meat. The results indicate that a rearing system with a cage pattern and a medium density is better than other arrangements for small-sized meat ducks.

The very large economic and social burdens of fracture-related complications make rapid fracture healing a major public health goal. The role of parathyroid hormone (PTH) in treating osteoporosis is generally accepted, but the effect of PTH on fracture healing is controversial. This meta-analysis was designed to investigate the efficacy and safety of PTH in fracture healing. The EMBASE, PubMed, and Cochrane Library databases were systematically searched from the inception dates to April 26, 2018. The primary randomized clinical trials comparing PTH treatment for fracture healing with placebo or no treatment were identified. We did not gain additional information by contacting the authors of the primary studies. Two reviewers independently extracted the data and evaluated study quality. This meta-analysis was executed to determine the odds ratio, mean difference, standardized mean difference, and 95% confidence intervals with random-effects models. In total, 8 randomized trials including 524 patients met the inclusion criteria. There were significant differences in fracture healing time, pain relief and function improvement. There were no significant differences in the fracture healing rate or adverse events, including light-headedness, hypercalcemia, nausea, sweating and headache, except for slight bruising at the injection site. We determined that the effectiveness and safety of PTH in fracture healing is reasonably well established and credible.

This study was performed to evaluate the effects of different rearing methods on the growth performance, carcass yield, and meat quality of small-sized meat ducks. A total of 420 healthy 21-day-old birds was randomly allocated to 2 treatment groups (6 replicates per treatment, sex ratio 1/1) and subjected to 2 rearing methods (furnished cage and plastic wire-floor) until d 63. Growth performance was measured in all birds. Three males and 3 females from each replicate were randomly selected and evaluated to determine the carcass yield and meat quality. In terms of growth performance, the rearing method affected the final body weight, average daily feed intake, and average daily gain, which were higher in the cage group ( P < 0.05) than in the floor group, with a similar feed/gain in both groups. For slaughter performance, ducks in the cage group showed a higher abdominal fat yield and lower gizzard yield than those in the floor group ( P < 0.05). For meat quality, the L* value of the breast muscle was higher in the cage group than in the floor group ( P < 0.05). The pH recorded at 1 h was lower and pH recorded at 24 h was higher in the cage group ( P < 0.05). The shear force and water loss rate were both lower in the cage group ( P < 0.05). Additionally, the moisture content was lower and intramuscular fat content was higher in ducks fed in cages ( P < 0.05). Our results indicate that the cage rearing system improved the growth performance and meat quality of ducks, which is appropriate for small-sized meat ducks.