Effects of dietary amylose to amylopectin ratio on growth performance,carcass quality characteristics and meat fatty acids in Chinese Qinchuan cattle

This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance,rumen fermentation and blood parameters,carcass characteristics and marbling score,and meat fatty acid profiles and transcriptional changes in the genes involved in the gluconeogenesis pathway in Chinese Qinchuan cattle.Forty-five cattle were randomly divided into three groups.The bulls were fed a control diet(middle amylose/amylopectin ratio=0.47)or diets with either waxy corn starch(WS)inclusion(low amylose/amylopectin ratio=0.23)or pea starch(PS)inclusion(high amylose/amylopectin ratio=0.60)for 90 days.The bulls were individually allowed to receive the diets at the daily amount of at least 2.1%of their individual BW twice daily.The bulls were weighed at 45-day intervals,and blood and rumen fluid samples were also collected at 45-day intervals.The bulls were slaughtered and longissimus thoracis(LT)samples were collected for meat quality measurements.Compared with PS,the average daily gain(ADG)and feed efficiency in control and WS were increased(P<0.05)during d 0 to 45.However,the feed efficiency in PS was increased(P<0.05)compared with the control and WS during d 46 to 90.During the whole feeding trial,the ADG in control and WS showed trends that were higher(0.05<P<0.1)than that of PS,while other growth performance measures and feed intake did not differ(P>0.05)among the three groups.Compared with PS,the serum insulin concentration in WS was increased(P<0.05)at d 45,but not at d 90.Compared with control and WS,the serum SOD and T-AOC concentrations in PS were increased(P<0.05)at d 45,but not at d 90.Compared with control,the rumen microbial crude protein contents in WS and PS were increased(P<0.05)at d 0,while those of control and WS were higher(P<0.05)than that of PS at d 45,but not at d 90.Compared with PS,the backfat thickness in control and WS were increased(P<0.05),however,the marbling score and expression of genes related to the gluconeogenesis pathway in liver of the three groups did not differ(P>0.05).Chemical and physio-chemical compositions of LT did not differ(P>0.05)among the three groups.In conclusion,diets with low or middle amylose/amylopectin ratios increased the backfat thickness,and tended to improve ADG,but had no effect on other carcass characteristics,fat content in the LT,or the expression of hepatic genes related to the gluconeogenesis pathway in Chinese Qinchuan cattle.

Effects of SNPs and alternative splicing within HGF gene on its expression patterns in Qinchuan cattle

Background： Identification of genetic variants, including SNPs（Single Nucleotide Polymorphisms）, CNVs（Copy Number Variations） and alternative splicing, within functional genes has received increasing attention in animal science research. HGF（Hepatocyte Growth Factor） is a very important growth factor that works as a mitogen or a morphogen during tissue growth, development and regeneration. However, to date, the functions of genetic variants within the bovine HGF gene, particularly their effects on m RNA expression, have not been determined well.Results： The present study aimed to perform association analysis between genetic variants and m RNA expression for the bovine HGF gene in Qinchuan cattle using various strategies, including PCR-RFLP（Restriction Fragment Length Polymorphism）, q PCR（Quantitative Real-time quantitative PCR）, TA cloning, DNA sequencing and bioinformatics analysis. A total of five SNPs were identified and only SV1 locus significantly affected HGF m RNA expression in fetal skeletal muscle（P 〈 0.05）. Heterozygous genotype individuals showed significantly higher HGF expression（P 〈 0.05）, which was significantly greater in the ＂CTCCAGGGTT＂ combined genotype than that in the＂CCCCGGGGTT＂ combined genotype（P 〈 0.05）. In addition, two alternative splicing variations, HGF-W and HGF-M,were identified, which resulted from alternative 3′ splice sites of exon 5, and HGF-W showed higher m RNA levels than HGF-M in all tissues.Conclusion： In summary, genetic variations within the HGF gene affected m RNA expression. These findings provide new insight into the molecular characteristics and functions of bovine HGF.

Differential expression of FOXO1 during development and myoblast differentiation of Qinchuan cattle and its association analysis with growth traits

Our previous work reported a relationship between FOXO1 mutations and growth of Qinchuan(QC) cattle. Here, we performed differential expression analysis of FOXO1 and its association analysis with growth traits in QC cattle. First, we measured the expression of the FOXO1 gene in nine tissues during three developmental stages. The results showed that FOXO1 was abundantly expressed in tissues of calves but was strongly repressed in adulthood, although there was significant transcription in skeletal muscle. FOXO1 expression showed gradual up-regulation during differentiation of primary bovine skeletal muscle cells.We also identified six SNPs of the bovine FOXO1 gene by sequencing DNA pools of samples from 488 individuals, and association analysis indicated that five SNPs were significantly associated with some growth traits in the QC population. We further analyzed four haplotype combinations of the six SNPs and found significant correlation with body length(P<0.01). In conclusion, FOXO1 participates in bovine myocyte differentiation and expression, and may be a strong candidate as a gene that affects growth traits that could be exploited in a QC cattle breeding program. More generally, our data provide a new theoretical basis for QC beef breeding and beef quality improvement.

Study on Population Genetic Characteristics of Qinchuan Cows Using Microsatellite Markers

To evaluate the genetic polymorphisms and to search for available molecular markers for Qinchuan cattle, 90 Qinchuan cows were genotyped with 12 microsatellite markers. A total of 247 alleles were detected, with the number of alleles ranging from 13 （INRA005） to 33 （HEL13）, giving a mean number of 21 alleles per locus. The total and mean effective allele number were 142.6229 and 11.8852, respectively. Mean sampling variance of the allele frequency was 2.6036 × 10^-4. Allele size ranges of the 12 microsatellite loci were different. The observed heterozygosity and expected heterozygosity were from 0.7842 （INRA005） to 0.9775 （BM315） and 0.7952 （BM315） to 0.9446 （HEL13）, respectively. Mean observed heterozygosity and mean expected heterozygosity were 0.9117 and 0.9047, respectively. Polymorphism information content values were from 0.7653 （INRA005） to 0.9420 （HEL13）, and mean polymorphism information content of the 12 microsatellite loci was 0.8965. All the 12 microsatellite loci were highly polymorphic, which showed that there were rich genetic polymorphisms at these detected microsatellite loci in Qinchuan cows. At the 12 microsatellite loci, the mean fixation index was -0.0076, reflecting that the degree of heterozygote defect at these loci was not high and deviations from Hardy-Weinberg equilibrium were not significant.