Preparation Of Rumen Protected Amino Acid Products And Effect On Nitrogen Metabolism In Inner Mongolia White Cashmere Goats

This paper developed a technique for preparation of rumen protected amino acid (RPAA) products, and evaluated availability of the RPAA products by in vitro and in situ trails, and meanwhile effect of RPAA on nitrogen metabolism in Inner Mongolia White Cashmere Goats (abbreviated IMWCG following) was studied.Part 1　Study on preparation of rumen protected amino acid products and evaluation of RPAA availability in the productsExp.1 Preparation of rumen protected amino acid productsFeed grade DL-Methionine and L-Lysine monohydrochloride (L-LysHCl) were encapsulated with different materials in wurster fluid-bed by spraying drying or cooling. Methionine was coated with stearic acid (Met-A), with crylic acid colophony (Met-B); with Hydroxypropyl-Methylcellulose (Met-C); with pH-sensitive ploymer (Met-D), respectively. Lysine was coated with stearic acid (Lys-A) or with glutin (Lysine-B). The result showed that tangential-spray coating technique was better than bottom-spray coating for DL-Methionine ,L-LysHCl, Met-A and Lys-A coated with stearic acids had a higher application efficacy than other coating materials.Exp.2 Evaluation of RPAA availability in the products by in vitro and the ruminal in situ techniquesIn vitro and the ruminal in situ techniques to simulate ruminant digestive tract(e.g. prerumen, rumen, abomasum)were used to identify the stability of the rumen-protected methionine (RPMet) and rumen-protected lysine (RPLys) in the prerumen and rumen of IMWCG, and its digestibility in the abomasum or duodenum. The coated amino acids were incubated for 2,4,8,12,16 and 24h in the artificial saliva,pH 6.6,5.4 citrate buffer liquid (to mimic prereminal condition), nylon bag in the rumen, and pH 2.4 citrate buffer liquid(to mimic postruminal condition). Results showed that Met-A consisted of DL-Methionine cores encapsulated with stearic acids and Lys-A consisted of L-LysHCl encapsulated with stearic acids relatively had a better stability in the artificial saliva, pH 6.6,5.4 citrate buffer liquid, by in situ trail and higher disappearance in pH 2.4 citrate buffer liquid than Met-B and Met-D. The lowest stability by in vitro trail was observed for the Methionine supplement coated with Hydroxypropyl Methylcellulose (Met-C) and for the lysine coated with glutin (Lysine-B). Part 2 Effect of RPAA products on amino acids fluxes and digestibility in the small intestine and nitrogen metabolism in Inner Mongolia White Cashmere GoatsExp.1 Effect of RPAA products on amino acids fluxes and digestibility in the small intestine of IMWCGNine growing wethers of IMWCG with the same father, fitted with permanent cannula at the rumen, T-shape cannula at the proximal duodenum and terminal ileum were used to investigate amino acids fluxes and digestibilities in different sites of the digestive tract of IMWCG fed the corn-soybean diet. The experimental goats were divided into three group in a free random block design as follow: Rumen protected amino acids group (A group), Normal amino acids group(B group), and Control group(C group).The experimental goats were fed diet with the same nitrogen level of a diet consisted of hay(70%), corn(19.65%),and soybean meal(4.5%). Co-EDTA was used as ruminal indigestible markers by in vivo trail to determine fluxes, profiles, and digestibility of amino acids at different sites of the small intestine of the goats.The results showed that the inclusion of RPMet and RPLys in the diet increased significantly DMI of the goats (p<0.05), and had a trend for a small increase of digestibility and disappearance of essential and total amino acids in the small intestine of IMWCG(p>0.05). Exp.2 Effect of RPAA products on nitrogen metabolism in IMWCGNine growing wethers of IMWCG with the same father, fitted with permanent cannula at the rumen, T-shape cannula at the proximal duodenum and terminal ileum and fed the basal diet supplemented with ruminally protected Met (RPMet) and Lys (RPLys), or with an unprotected form. Total collection of feces and urine was performed every 24h for 5d, to inv...