This study investigated the effect of replacing part of the dietary soybean meal with either polymer-coated urea or gelatinized starch urea on the production performance, blood indexes, and ruminal fermentation of Angus heifers. A total of 210 purebred Angus cattle (BW = 314.26 kg) were divided into three groups: the no urea group (CON), the polymer-coated urea group (PCU), and the gelatinized starch urea group (GSU); 20 g/kg polymer-coated urea or 25 g/kg gelatinized starch urea was used to replace part of soybean meal in the concentrate feed, according to the principle of isometabolic energy and isonitrogenous. The result showed that the PCU group had higher ADG and ADF apparent digestibility, while it had a lower feed–weight ratio. On the 86th day, the serum albumin (ALB) content in the PCU group was significantly higher than that in the CON group. In rumen, compared with the CON group, the contents of acetic acid and total volatile fatty acid were significantly higher in the PCU group, whereas butyric acid and propionic acid were significantly higher in the PCU group and GSU group. Ruminal bacterial diversity analysis found that the abundance of Firmicutes was higher in the PCU group at the phylum level, and an inverse result was observed in Bacteroidetes. The abundance of Paraprevotella was higher in the PCU group, whereas higher abundance of Prevotella was found in the GSU group at the genus level. These results indicate that slow-release urea can replace part of soybean meal in the diet, and the amount of substitution in this trial had no diverse effect on the performance of Angus heifers.

This study investigated the effect of replacing part of the dietary soybean meal with either polymer-coated urea or gelatinized starch urea on the performance, nutrient digestibility, blood biochemical indexes, ruminal fermentation and rumen microflora of Angus heifers. The urea release profiles of two kinds of slow-release urea were evaluated in vitro and indicated a superior nitrogen retention with the polymer-coated urea. 210 purebred Angus cattle (BW = 314.26 kg) were divided into three groups: no urea group (CON), polymer-coated urea group (PCU), gelatinized starch urea group (GSU), 20g/kg polymer-coated urea or 25g/kg gelatinized starch urea was used to replace part of soybean meal in the concentrate feed respectively according to the principle of iso-metabolic energy and iso-nitrogenous. During the whole experiment, the ADG of PCU group was higher than both the GSU group and the CON group. The feed-weight ratio of the PCU group was significantly lower than both the GSU group and the CON group during the 90-day feeding period. The ADF apparent digestibility in the PCU group was significantly higher than that of the CON group, and extremely significantly higher than that of the GSU group. On the 86th day, the ALB content in the PCU group was significantly higher than that in the CON group. The contents of acetic acid and butyric acid, total volatile fatty acid and propionic acid were significantly higher in the PCU group than in the CON group. Bacterial diversity analysis found that the abundance of Firmicutes was higher in the PCU group than that in the GSU group and the CON group at the phylum level, and inverse result was observed in Bacteroidetes. The abundance of Paraprevotella was higher in the PCU group, whereas higher abundance of Prevotella was found in the GSU group at the genus level. These results indicate that both polymer-coated urea and gelatinized starch urea can replace part of soybean meal in the diet, and the amount of substitution in this trial had no diverse effect on the performance of Angus heifers, and the effect and economic benefits brought by polymer-coated urea were better than gelatinized starch urea.

In this study, we investigated the effects of lentinan (LNT) on hematological parameters, immune indices, and metabolite levels in dairy cows. We randomly assigned forty Holstein cows to four treatment groups. The treatments consisted of 0, 5, 10, and 15 g/d of LNT. Compared with the control group, the addition of 10 g/d of LNT decreased the content of ALT and IL-8 but simultaneously increased the content of IL-4 in the cows’ serum. Supplementation with 10 g/d of LNT decreased the levels of lymphocyte, RDW, ALT, AST, TC, IL-2, and IL-8, but, concurrently, in-creased the levels of granulocytes and IL-4 in their serum. In addition, supplementation with 15 g/d of LNT decreased the levels of RDW, TC, IL-2, and IL-8, but, at the same time, increased the levels of IL-4 and IgM in their serum. For the metabolomic analysis, cows fed with 0 and 10 g/d of LNT were selected. The results showed that 10 metabolites, including reduced nicotinamide riboside and trehalose, were upregulated in the 10 g/d group. These differential metabolites were enriched in tyrosine metabolism and trehalose degradation and altered two metabolic pathways of ubiquinone and other terpene quinone biosynthesis, as well as starch and sucrose metabolism. These findings provide evidence that LNT could be used to reduce the risk of inflammation in dairy cows.

Lentinan (LNT) is a bioactive polysaccharide that has been proven to improve the production performance of animals. The objective of this study was to investigate the effects of LNT on lactation performance and rumen fermentation in dairy cows. Through random block design, 80 Holstein cows were randomly assigned to four treatments (CON, control group, fed a basal diet; and 5LNT, 10LNT, 15LNT groups, fed a basal diet with 5, 10, 15 g/d LNT, respectively) according to the days in milk (57 ± 21.3 d), milk yield (42.3 ± 7.88 kg/d) and parity (3.44 ± 1.45). Each treatment had 20 replicates of one cow each. The results showed that there was a linear increment in the production of milk (P = 0.034, increased by 3.28 kg/d), milk protein (P = 0.020, increased by 76.04 g/d) and lactose (P = 0.003, increased by 213.07 g/d) with the increase in LNT doses. In addition, the apparent digestibility of crude protein (CP) linearly increased with the increasing LNT supplementation (P = 0.008, increased by 15.42%). In terms of ruminal fermentation, oxidation-reduction potential value (P = 0.001, reduced by 35.89), the proportion of acetate (P = 0.004, reduced by 8.91%) and acetate to propionate ratio (A/P; P = 0.002, reduced by 1.27) linearly decreased, while the proportion of propionate (P = 0.003, increased by 6.42%) and butyrate (P = 0.037, increased by 2.49%) linearly increased with the increase in LNT dosages. The changes in ruminal fermentation parameters led to changes in the ruminal microbiota and metabolites. Supplementation with LNT increased the relative abundance of some beneficial bacteria, such as Muribaculaceae and Lachnospiraceae (P < 0.05), and decreased the relative abundance of some harmful bacteria, such as Rhodobacteraceae, Tyzzerella, Lysinibacillus and Turicibacter (P < 0.05). Moreover, LNT supplementation up-regulated 2-(pyridin-2-ylamino) benzoic acid and hippuric acid (P < 0.05), which could promote phenylalanine metabolism, and down-regulated some metabolites inhibiting arginine biosynthesis, like 2-methylglutaric acid and N2-acetylornithine (P < 0.05). Moreover, lentinan supplementation significantly elevated 2-(pyridin-2-ylamino)benzoic acid (Py-PABA) and hippurate (P < 0.05), metabolites associated with enhanced phenylalanine metabolism, while reducing inhibitors of arginine biosynthesis such as 2-methylglutaric acid and N²-acetylornithine (P < 0.05). In conclusion, supplementation of LNT could improve the ruminal microbiota and metabolism and further affect the lactation performance of cows.