Transfer of β-hydroxy-β-methylbutyrate from sows to their offspring and its impact on muscle fiber type transformation and performance in pigs

Background： Previous studies suggested that supplementation of lactating sows with β-hydroxy-β-methylbutyrate（HMB） could improve the performance of weaning pigs, but there were little information in the muscle fiber type transformation of the offspring and the subsequent performance in pigs from weaning through finishing in response to maternal HMB consumption. The purpose of this study was to determine the effect of supplementing lactating sows with HMB on skeletal muscle fiber type transformation and growth of the offspring during d 28 and180 after birth. A total of 20 sows according to their body weight were divided into the control（CON, n = 10） or HMB groups（HMB, n = 10）. Sows in the HMB group were supplemented with β-hydroxy-β-methylbutyrate calcium（HMB-Ca） 2 g/kg feed during d 1 to 27 of lactation. After weaning, 48 mixed sex piglets were blocked by sow treatment and fed standard diets for post-weaning, growing, finishing periods. Growth performance was recorded during d 28 to 180 after birth. Pigs were slaughtered on d 28（n = 6/treatment） and 180（n = 6/treatment） postnatal and the longissimus dorsi（LD） was collected, respectively.Results： The HMB-fed sows during lactation showed increased HMB concentration（P ＆lt; 0.05） in milk and LD of weaning piglets（P ＆lt; 0.05）. In addition, offsprings in HMB group had a higher finishing BW and lean percentage than did pigs in CON group（P ＆lt; 0.05）, meanwhile, compared with pigs from sows fed the CON diet, pigs from sows fed HMB diet showed higher type Ⅱ muscle fiber cross-sectional area（CSA）, elevated myosin heavy chain（MyHC） Ⅱb and Sox6 mRNA, and fast-MyHC protein levels in LD（P ＆lt; 0.05）.Conclusions： HMB supplemented to sow diets throughout lactation increases the levels of HMB in maternal milk and skeletal muscle of pigs during d 28 after birth and promotes subsequent performance of pigs between d 28 and 180 of age by enhancing glycolytic muscle fiber transformation.

Effects of Dietary Yeast Cell Wall Polysaccharides Supplementation to Late Gestation and Lactation Diets on Reproductive Performance and Blood Profiles of Sows and Their Offspring

This study was conducted to determine the effects of yeast cell wall polysaccharides（YCWP） on reproductive performance, serum profiles and milk composition during late gestation and lactation. A total of 96 sows（Landrace × Yorkshire） were blocked on a basis of breed, parity（2-3）and their respective d 85 of gestation, and then randomly allotted to the following three dietary treatments： CON（basal diet, treatment 1）, YCWP1（CON＋0.2% YCWP, treatment 2） and YCWP2（CON＋0.4% YCWP, treatment 3）. The experiment lasted from d 85 of gestation to weaning（d 21 of lactation）. Sows fed YCWP diets had lower backfat thickness reduction from postpartum to weaning（ P〈0.05）. The supplementation of YCWP tended to increase litter weight at weaning（P=0.08） compared with CON. The non-lipid and total milk solids in colostrum was improved by YCWP2（P〈0.05）.No differences were observed in milk composition among dietary treatments（ P〉0.05）. The supplementation of YCWP decreased（P〈0.05） the levels of alanine amino transferase（ALT）, aspartate amino transferase（AST）, while it did not affect（ P〉0.05） alkaline phosphatase（ALP）, total protein（TP）,albumin（ALB）, globulin（GLB）, glucose（GLU）, total cholesterol（TC）, triglyceride（TG） or immunoglobulin G（IgG） in the sow serum. The serum IgG of piglets was increased by the YCWP. The levels of serum ALT and AST were reduced（P〈0.05） for suckling piglets in YCWP treatments. Taken together, the results of current studies might indicate beneficial effects of YCWP supplementation to late gestation and lactation diets on the sow productivity by improving litter weight at weaning, reducing backfat loss, and increasing serum IgG concentrations of piglets.

Experimental study on the performance of bowl-tray rice precision seeder

In order to optimize the parameters of bowl-tray rice precision seeder and improve its performance,three major factors respectively at five levels,including shaped hole diameter,vertical displacement of rice seeds and rotating speed of cam,were tested,the quadratic orthogonal rotational regression experiments were conducted,and the effects on seeding rate,leakage sowing rate and the injury rate were investigated.The test results show that factors affecting rice seeding rate are in the order of shaped hole diameter,rotating speed of cam and vertical displacement of rice seeds.The factors affecting rice planting leakage rate are in the order of shaped hole diameter,vertical displacement of rice seeds and rotating speed of cam,and the factors affecting rice injury rate are in the order of rotating speed of cam,vertical displacement of rice seeds and shaped hole diameter.Optimal parameters(shaped hole diameter:10 mm,vertical displacement of rice seeds:27 mm,rotating speed of cam:13 r/min)and performance index(seeding rate:95.43%,leakage sowing rate:0.37%,injury rate:0.58%)provided the basis for design and performance improvement of the bowl-tray rice precision seeder.