Effects of Dietary Carbohydrate and of Intestinal Microflora on Excretion of Endogenous Amino Acids by Poultry

Abstract

The effects of dietary carbohydrate and of intestinal microflora on excretion of endogenous amino acids by poultry were investigated. Excretion of endogenous amino acids was compared among fasted roosters, intact roosters fed low- or high-fiber, N-free diets, and surgically-modified (SM) roosters fed a low-fiber, N-free diet. The low-fiber diet contained 50% corn starch, 45% glucose, and 5% cellulose, whereas the high-fiber diet contained 25% each of corn starch, glucose, and raw potato starch, 17.5% cellulose, and 7.5% pectin. Digesta were obtained from the terminal ileum of SM roosters to eliminate effects of the microflora in the large intestine and ceca. The roosters were force-fed 60 g of the appropriate diet (30 g at the initiation of the trial followed by an additional 30 g 6 hours later). Excreta or digesta and urine were collected quantitatively for 48 hr after the first force-feeding. Roosters fed the high-fiber diet excreted substantially more (P less than .05) amino acids than did fasted roosters or roosters fed a low-fiber diet. Excreta from roosters fed the high-fiber diet contained higher (P less than .05) levels of alanine and aspartic acid than excreta from fasted or digesta from SM roosters, indicating substantial microbial synthesis of amino acids in the gut. In contrast, amino acid composition of excreta from fasted and intact roosters fed the low-fiber diet was similar to that of digesta from SM roosters, suggesting less microbial influence. Excretion of glucosamine plus galactosamine by SM roosters was approximately twice that of intact roosters fed the same diet. Glycine was the most abundant amino acid in digesta of SM roosters. Results of this study indicate that dietary carbohydrate substantially affects excretion of endogenous amino acids by poultry and that fasted birds may not provide an accurate estimate of endogenous amino acid excretion for birds fed high-fiber feedstuffs in amino acid digestibility trials.

Analysis of the LIV System of Campylobacter jejuni Reveals Alternative Roles for LivJ and LivK in Commensalism beyond Branched-Chain Amino Acid Transport

“…Studies have verified the importance of a serine transporter (SdaC), a serine deaminase (SdaA), an aspartase (AspA), and an aspartate:glutamate aminotransferase (AspB) for both in vitro growth and commensal colonization of avian species by C. jejuni (11,41). In addition, these amino acids are found most abundantly in chick feces, indicating that these nutrients are likely available for C. jejuni in infected hosts (35). Other amino acid transporters such as the Paq glutamine transport system have been shown to alter the virulence properties of the bacterium (28).…”

Estimation of Bioavailable Amino Acids in Feedingstuffs for Poultry and Pigs: A Review With Emphasis on Balance Experiments

“…The AA excretions of fasted cecectomized birds were generally larger than those of intact birds (Kessler et al 1981;Parsons 1984) but when similar birds were given small amounts of N-F diets there were few differences due to cecectomy (Parsons et al 1983;Parsons 1984 however, in another report (Raharjo and Farrell 1984a) The data of Kessler et al (1981) (1983) (Anonymous 1966) but addition of free AA to a diet does not alter total absorption (Rolls etal. 1972); however, certain small peptides can inhibit AA uptake (Shorrock and Ford 1978).…”

“…a N-F diet was associated with greater outputs of l0 AA than was fasting (Muztar and Slinger 1980c). Parsons et al (1983) also found that, in intact birds, the AA excretion increased from fasting to a N-F diet and within N-F diets as fiber concentration increased; however, cecectomized, colostomized birds fed the low-fiber N-F diet had outputs similar to fasted intact birds.…”

“…The effect of cecectomy on the AMAA in several feedingstuffs was small and inconsistent (Raharjo and Farrell 1984b). When low-fiber, N-F diets were fed to intact cockerels and to cecectomized, colostomized cockerels the amounts of AA excreted were similar but greater than the amounts excreted by fasted intact birds (Parsons et al 1983).…”

Histological Changes of Small Intestinal Mucosa of Cocks Due to Sunflower Meal Single Feeding

“…High levels of fiber also reduce the time of feed passage throughout the digestive system (Johnson, 1981). Furthermore, fiber may cause abrasion of the intestinal mucosa and thus increase the amino acid requirements for the synthesis of mucosal cells (Parsons et al, 1983).…”