Effect of dietary inclusion of graded levels of distillers dried grains with solubles on the performance, blood profile and rumen microbiota of Najdi lambs

Abstract

An experiment was conducted in a completely randomized design to evaluate the effect of including graded levels (0, 20, 30, 40 and 50% of diet) of dried distiller's grains with solubles (DDGS) on growth performance, slaughter parameters, blood serum metabolites and rumen microbiota in weaned Najdi male lambs. Thirty-five lambs, initial body weight of 33.45 ± 0.75 kg, and approximately three-month old were used in a 94-day feeding experiment. Performance measurements were conducted biweekly and blood samples were collected monthly. Inclusion of DDGS in the diets of growing Najdi lambs at levels up to 50% did not affect body weight gain (BWG) compared with the lambs fed the control diet (CON, 0% DDGS). Lambs fed the 50% DDGS diet consumed less feed compared with lambs in other groups (98 vs 112.5 kg DM) but had no adverse effect on BWG. Rumen pH values at 0, 6, 12 and 18 h post feeding and concentrations of blood serum total proteins, glucose, triglycerides, urea-N or albumin were similar across treatments. Slaughter parameters including slaughter weight, hot and cold carcass weights and dressing % (hot and cold carcass) were not affected by the treatments. There was no difference in the weights of full compartmental stomach and intestines, liver, omental fat, Kidney Knob and Channel Fat (KKCF) and tail fat between DDGS treatments and CON. The study concluded that the inclusion of DDGS in the diets of growing Najdi lambs had no adverse effects on growth performance and slaughter parameters. Rumen microbiota was not affected, however, our data suggest significant interactions between DDGS and selected bacterial groups and DDGS driven rearrangement of Prevotella species.

Keywords: Blood profile; Carcass characteristics; DDGS; Growth performance; Najdi lambs; Rumen microbiota.

Figure 1

Sequencing quality and microbial composition of rumen fluid overview. A: Sequencing quality check showing a number of sequences per sample bar-chart; B: Distribution of bacterial phyla across the treatments; C: Clustered bar-chart of the 20 most abundant genera.

Figure 2

Discriminant Analysis of Principal Components (DAPC) plot at an OTU level.

Figure 3

Correlation of taxa with the concentration of DDGS: Phylum Verrucomicrobia comprised of Unclassified RFP12 genus, and genus Olsenella were positively correlated with DDGS concentrations.

Figure 4

Correlation of taxa with the concentration of DDGS at an OTU level.

Figure 5

Genus level network presenting correlations between the top 20 most abundant genera with each other and DDGS concentrations. Red line (edge) presents a positive and blue line negative Spearman correlation. Nodes are coloured by phylum membership and sized according to relative abundance.

Figure 6

An OTU level network presenting correlations between the top 20 most abundant genera with each other and DDGS concentrations. Red line (edge) presents a positive and blue line negative Spearman correlation. Nodes are coloured by phylum membership and sized according to relative abundance.