Effects of dietary protein sources and nisin on rumen fermentation, nutrient digestion, plasma metabolites, nitrogen utilization, and growth performance in growing lambs1

Abstract

This study investigated the effects of dietary protein sources and nisin on rumen fermentation, nutrient digestion, plasma metabolites, N utilization, and growth performance in growing lambs. Thirty-two male Hu lambs (23 ± 2 kg initial BW) were assigned to four dietary treatments in a randomized block design with a 2 × 2 factorial arrangement. Two protein sources, soybean meal (SBM) and dried distillers grains with solubles (DDGS), and two levels of nisin, 0 and 30.5 mg of nisin/kg of feed, were used to formulate four isonitrogenous and isoenergetic diets. No interaction (P ≥ 0.16) of protein × nisin was found except on apparent digestibility of DM, OM, NDF, and ADF (P ≤ 0.02). Lambs receiving DDGS had lower (P ≤ 0.04) concentrations of ruminal acetate and butyrate, but propionate concentrations did not differ (P = 0.39), compared with those fed SBM, leading to a trend for reduced total VFA concentration (P = 0.07). Ruminal NH3-N and total branched-chain VFA concentrations were lower (P ≤ 0.01) in the lambs fed DDGS than in those fed SBM. The DDGS-fed lambs had less (P < 0.01) CP, but greater (P < 0.01) ether extract apparent digestibility than those fed SBM. For plasma metabolites, only blood urea N and albumin concentrations were lower in the DDGS-fed lambs (P < 0.01) than in those fed SBM. Nitrogen excretion pathway was altered when DDGS replaced SBM, with fecal N excretion (% of N intake) being greater (P < 0.01), while urinary N excretion (% of N intake) tending to be less (P = 0.06) from the DDGS-fed lambs than those fed SBM. Protein sources affected growth performance in an age/time-dependent manner. From weeks 1 to 4, DDGS resulted in less (P = 0.03) DMI and ADG than SBM. From weeks 5 to 8, DDGS did not affect (P ≥ 0.23) DMI or ADG but resulted in a greater (P = 0.04) G:F than SBM. Final BW did not differ (P = 0.58) duo to protein source. Providing nisin had no impact on DMI (P = 0.44), ADG (P = 0.84), or G:F (P = 0.73). Nisin addition only affected plasma uric acid concentration (P = 0.04). It was concluded that DDGS could substitute for SBM as a nitrogen source to growing Hu lambs to reduce N excretion via urine without adverse effects on animal performance, but nisin supplementation probably had no additional benefits.

Garlic skin induced shifts in the rumen microbiome and metabolome of fattening sheep

“…In total, 139 metabolites were changed as a result of garlic skin supplementation, 93 out of 139 signi cantly different metabolites had higher concentration including amino acids, dipeptides, fatty acids, and carbohydrates in GAS-fed lambs compared with CON-fed lambs. These amino acids and dipeptides can be used as precursors for the synthesis of microbial protein, while carbohydrates and fatty acids can provide energy for the synthesis of microbial protein [48]. Additionally, our study also demonstrated pyrimidine and purine metabolism pathways were changed in GAS-fed lambs.…”

“…Ruminal uid (approximately 25 mL) was collected using an oral stomach tube immediately prior to feeding on the last day of the trial as described by Shen et al (2018) [48]. The pH of the ruminal uid sample was measured immediately after collection using a portable pH meter (Ecoscan pH 5, Eutech Instruments, Singapore).…”

Effects of dietary replacement of soybean meal with dried distillers grains with solubles on the microbiota occupying different ecological niches in the rumen of growing Hu lambs

“…However, the influences of DDGS addition on rumen microbial community structure and function in growing lambs remain poorly understood. In our previous study using growing lambs, substituting DDGS for SBM in an isonitrogenous diet increased dietary EE, neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents, and significantly altered rumen fermentation parameters such as volatile fatty acid (VFA) and ammonia concentrations [5].…”

Effect of dried distillers grains (DDGS) on diet digestibility, growth performance, and carcass characteristics in Creole wool lambs fed finishing diets

“…In lambs, 20% inclusion of DDGS did not affect the dry matter intake (DMI) (Schauer et al, 2008) and improved weight gain (Felix et al, 2012), but when 25% of DDGS was included in the diet, the concentration of ammonia nitrogen in the rumen and the digestibility of DM decreased (Uwituze et al, 2010). However, DDGS could replace soybean meal as a nitrogen (N) source for growing lambs to reduce N excretion without adversely affects animal performance (Shen et al, 2018).…”