The Inclusion of Concentrate with Quebracho Is Advisable in Two Forage-Based Diets of Ewes According to the In Vitro Fermentation Parameters

Effects of Mowing Times on Nutrient Composition and In Vitro Digestibility of Forage in Three Sown Pastures of China Loess Plateau

Mowing, Mowing, which affects the nutritional levels of grasslands, is the main utilization of sown pasture. We sowed alfalfa monoculture grassland, tall fescue monoculture grassland and tall fescue + alfalfa mixed grassland in typical steppe of the Loess Plateau to investigate the nutrient compositions and in vitro degradability of those three grasslands under different mowing stubble times and to provide reference for nutrient management of sown pastures. The results showed that the stubble time significantly affected (p < 0.05) the nutrient compositions and mineral elements of forages in alfalfa monoculture grassland, whereas had no effects on the nutrient compositions and dry matter digestibility of forages in tall fescue monoculture grassland and alfalfa + tall fescue mixed grassland. The relative feeding value of mixed grassland of alfalfa and tall fescue was increased by 2.6−22.4% as compared to monoculture grasslands. The model constructed based on forage nutrient content could accurately predict the forage dry matter degradability of alfalfa monoculture, tall fescue monoculture and mixed alfalfa and tall fescue, respectively.

Dietary Concentrate-to-Forage Ratio Affects Rumen Bacterial Community Composition and Metabolome of Yaks

Changes in dietary composition affect the rumen microbiota in ruminants. However, information on the effects of dietary concentrate-to-forage ratio changes on yak rumen bacteria and metabolites is limited. This study characterized the effect of three different dietary concentrate-to-forage ratios (50:50, C50 group; 65:35, C65 group; 80:20, C80 group) on yak rumen fluid microbiota and metabolites using 16S rRNA gene sequencing and liquid chromatography-mass spectrometry (LC-MS) analyses. Rumen fermentation parameters and the abundance of rumen bacteria were affected by changes in the dietary concentrate-to-forage ratio, and there was a strong correlation between them. At the genus level, higher relative abundances of norank_f__F082, NK4A214_group, Lachnospiraceae_NK3A20_group, Acetitomaculum, and norank_f__norank_o__Clostridia_UCG-014 were observed with a high dietary concentrate-to-forage ratio (P < 0.05). Combined metabolomic and enrichment analyses showed that changes in the dietary concentrate-to-forage ratio significantly affected rumen metabolites related to amino acid metabolism, protein digestion and absorption, carbohydrate metabolism, lipid metabolism, and purine metabolism. Compared with the C50 group, 3-methylindole, pantothenic acid, D-pantothenic acid, and 20-hydroxy-leukotriene E4 were downregulated in the C65 group, while spermine and ribose 1-phosphate were upregulated. Compared to the C50 group, Xanthurenic acid, tyramine, ascorbic acid, D-glucuronic acid, 6-keto-prostaglandin F1a, lipoxin B4, and deoxyadenosine monophosphate were upregulated in the C80 group, while 3-methylindole and 20-hydroxy-leukotriene E4 were downregulated. All metabolites (Xanthurenic acid, L-Valine, N-Acetyl-L-glutamate 5-semialdehyde, N-Acetyl-L-glutamic acid, Tyramine, 6-Keto-prostaglandin F1a, Lipoxin B4, Xanthosine, Thymine, Deoxyinosine, and Uric acid) were upregulated in the C80 group compared with the C65 group. Correlation analysis of microorganisms and metabolites provided new insights into the function of rumen bacteria, as well as a theoretical basis for formulating more scientifically appropriate feeding strategies for yak.

Effect of the maternal feeding on the carotenoid and tocopherol content of suckling lamb tissues

The objectives of the present study were to quantify the deposition of carotenoids and tocopherols in the tissues of suckling lamb and to use the levels of those compounds to trace the maternal feeding. Twenty suckling lambs were raised with their dams in vegetative-stage pastures, and 19 suckling lambs were stalled indoors with dams that received hay ad libitum, until the lambs reached 10-12 kg. The lambs' weekly intake of carotenoids and tocopherols was estimated from the milk production of the ewes and the carotenoid and tocopherol content of the milk. Samples of the subcutaneous and perirenal fat, longissimus thoracis muscle, and liver of the suckling lambs were collected at 24 h after slaughter. The pasture-raised lambs had greater intake of lutein than their indoor counterparts throughout the suckling period (p < 0.05), more retinol during the second and third weeks of the suckling period (p < 0.05), and more α-tocopherol during the first three weeks of the suckling period (p < 0.05), being similar thereafter. The pasture-raised lambs, when compared to the lambs raised indoors, had greater lutein content in the muscle and liver (p < 0.001), retinol and α-tocopherol content in all tissues (p < 0.001) and muscle and liver γ-tocopherol content (p < 0.05). The maternal feeding could be accurately predicted from the carotenoid and tocopherol content of whole lamb carcasses and muscle tissue but not from those of ewes' milk, lamb liver tissue or lamb fat deposits.