EFFECT OF PROTEIN-ENERGY SUPPLEMENTATION ON RUMEN KINETICS, METABOLITE PROFILE AND GROWTH PERFORMANCE OF RAMS FED HIGH FIBRE DIETS

Abstract

Three Experiments were conducted with overall aim of evaluating the nutritive value of selected feedstuffs using rams. In one prefeeding trial, results showed that five to ten-minute boiling of blood did not elicit significant difference (P>0.05) in the chemical composition, in-situ rwnen degradability and amino acid profile of the blood meal. Results of urea ensilage of sorghum stover (SS) showed that ensilage beyond ten days led to loss of vital nutrients. The In-situ (degradability) and In-vitro (gas production) rwnen kinetic indices were suggestive of the extent of urea fermentation of sorghum stover and chemical composition of other high fibre feedstuffs. In Experiment 2, the lower dry matter intake (DMI) in the groundnut cake(GNC): cotton seed cake(CSC) (60:40) diets (207.54 and 165.69g1day for diets 3 and 6 respectively) as against higher values for CSC diets (360.85 and 368.77g/day for diets 2 and 5 respectively) showed that improved apparent digestibility was associated with reduced intake. There was significant difference (P<O.05) between CSC-supplemented diets and those ofBM and GNC:CSC (60:40) in their mean daily liveweight gain (LWG), mean feed conversion ratio and mean digestible DMI. In Experiment 3, high protein diets (HPD) recorded lower nitrogen (N) retention rate (312g1day) than medium protein diets (MPD) with corresponding value of 5.01g/day.The consistent increase in urinary N losses (7.08,9.25 and 13.52g1day for low protein diets (LPD), MPD and HPD respectively) and faecal N losses (4.60,6.94 and 12.17g1day for LPD, MPD and HPD respectively) reflected the increase and subsequent drop in N retention between the diets (2.86, 5.01 and 3. 12g,'day for LPD, MPD and HPD respectively). Results also showed that much further addition of crude protein(CP) above 154.70glkgDM was wasteful. Although relatively higher than common, rumen ammonia (137.33, 155.00 and 168.61 mg/L) and volatile fatty acids (VFA) (75.35, 98.22 and 106.42mmol/L) for LPD, MPD and HPD respectively complemented each other. Calculated microbial N supply were 56.02, 64.098 and 65.40glkg DOMR (digestible organic matter fermented in the rumen) for LPD, MPD and HPD respectively. Since these values were found to be higher than mean microbial N yield of 32g / kgDOMR reported by ARC (1984), it showed that the experimental diets exceeded minimum requirements for microbial protein synthesis to support production. The results were a proof of the efficacy of the Purine Derivative (PD)Technique in evaluating Ruminant Feedstuffs.