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Yak (Bos grunniens) is an animal mainly living on the Tibetan Plateau. Yak skin is a valuable resource that is wasted in the meat production process. This study aimed to prepare yak skin gelatin hydrolysates (YSGH) from yak skin through enzymatic hydrolysis and investigate functional characterization of YSGH. We showed that trypsin was more effective than neutrase, papain, and pepsin in increasing the degree of hydrolysis (DH) of YSGH. The conditions of enzymatic hydrolysis were optimized using central composite design (CCD) and response surface method (RSM), and the highest DH value of 31.96% was obtained. We then analyzed the amino acid compositions and molecular weight distribution of peptides in YSGH. The obtained YSGH exhibited certain antioxidant activity and excellent ACE-inhibitory activity (IC50 = 0.991 mg/mL). In addition, the solubility (98.79%), emulsification, and foaming properties of YSGH developed here were also evaluated. With these physicochemical and biological functions, YSGH had potential applications in food, pharmaceuticals, and cosmetics as an ingredient.

The kinds and proportions of triglycerides of human mature milk play an independent role in the growth of infants. In this study, the human milk samples obtained from eight different Chinese cities (Chengdu, Weihai, Lanzhou, Jinhua, Beijing, Guangzhou, Zhengzhou, and Harbin) and six sequential mature lactation times (30, 60, 90, 120, 150, and 180 days) were detected for the triglycerides. The result demonstrated that total 66 triglycerides were detected in mature human milk, with acyl carbon number (ACN) numbers were locating in the range of 34–54 and double bond (DB) numbers were locating in the range of 0–6. In addition, the percentage of OPO, OPL, and OOO was relatively higher than others, accounted for more than 4% of total triglycerides in all the lactation areas and times, and the percentage of U2S and LLL triglycerides was also richest in mature milk. Furthermore, it was obvious that lactation regions had more significant effect on the triglycerides compared with lactation time and the triacylglycerols (TAGs) of human milk in Guangzhou were clearly different from that in other regions. Therefore, the results of this study will provide data reference for the design of infant formula suitable for Chinese babies.

The study investigated the use of dried goat rumen contents (DGRC) on growth performance of broiler chickens. Rumen contents were obtained from goats immediately after slaughter during the wet season, sundried, milled and incorporated in experimental diets at levels of 0, 5 and 10%. The 0% DGRC diet was the control. The experimental diets were formulated on iso-caloric and iso-nitrogenous principles in line with the nutritional requirements for growing broiler birds. Experimental birds were first fed on a common starter broiler diet comprising of 21% CP and 3100 Kcal/kg feed from 0 to 21 days of age; thereafter the birds (21-42 days) were allotted to the experimental treatments in a completely randomized design (CRD) with three replications. A cage with 10 birds was the experimental unit. Experimental diets were offered in the morning and evening, water was provided ad lib. Feed offered and leftovers were weighed daily, and body weight changes were recorded on a weekly basis. The results showed that birds on the 5% diet had significantly (Linear, Quadratic P<0.05) higher final body weights (FBWs), average daily gain (ADG) and better feed conversion ratio (FCR) compared to those o on diets with 0 and 10% DGRC. Apparent and ileal digestibility of nutrients was improved with incorporation of dried goat rumen contents in the diets. Sensory analysis showed that meat from birds on 5% DGRC diet had (P<0.05) more oil content and softer meat across diets. It is concluded that, use of dried goat rumen contents (DGRC) in broiler diets improves growth performance and organoleptic qualities of broiler chicken meat.

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