Replace part of regenerative rice silage feed with whole cottonseed enhances growth performance and nutrient digestibility via regulating gH/IGF axis in beef cattle

This work was designed to assess the impacts of whole cottonseed (WCs) on growth performance, nutrient digestion, GH /IGF-1 axis, and meat quality in beef cattle. Twenty-four healthy male simmental cattle (18 months old and 370.5 ± 12.5 kg) were arbitrarily classified into two groups (n=12 per group): Control group (without WCs) and WCs replaced group (part of regenerative rice silage was replaced with WCs). The dry matter intake (DMI) was declined(P < 0.01), while the average daily gain (ADG) was increased(P < 0.05), therefore the feed conversion ratio (FCR) was lower (P < 0.05) in WCs replaced group. Beef cattle consuming WCs had a higher digestibility of total gastrointestinal nutrients (P < 0.01 or P < 0.05). The growth hormone receptor (GHR), insulin-like growth factor 1 (IGF-1), and insulin-like growth factor 1 receptor (IGF-1R) mRNA amounts were all enhanced (P < 0.05) in liver, longissimus dorsi muscle, and semitendinosus muscle of beef cattle after feeding WCs relative to control group. The mRNA amounts of phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), and ribosomal protein S6 kinase beta-1 (S6K1) and the protein phosphorylation levels of Akt、mTOR, and S6K1 were all markedly enhanced (P < 0.05 or P < 0.01) in liver, longissimus dorsi muscle, and semitendinosus muscle for WCs replacement. The shear force and cooking loss values having somewhat raised(P < 0.05) for WCs replacement. Altogether, WCs improves the growth performance and nutrient digestibility via regulating GH/IGF axis in beef cattle, and has negative effects on meat quality.