Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 134 THE EFFECT ON GROWTH OF SUPPLYING GLUCOSE CONTINUOUSLY INTO THE DUODENUM OF LAMBS ON LOW-PROTEIN DIETS R.A. LENG*, S. ECONOMIDES #* and F.M. BALL* The requirements of/ growing ruminants for glucose and amino acids appear to be interdependent. In an earlier study from this laboratory, lambs given diets containing different levels of bypass protein were also supplemented with different levels of glucose. Glucose availability was manipulated by using suckling lambs in which the oesophageal groove reflex was maintained, and the glucose was given in several discrete feeds over15 hours. A response to glucose was achieved only when the diet contained adequate amounts of bypass protein (Kempton, Hill & Leng, 1978). Glucose is stored in the body as glycogen. Since the capacity of the glycogen stores is small, it seemed possible there could have been metabolic difficulty in disposing of-high levels of glucose after feeding, and this may have affected the previous results. It was therefore decided to re-examine the responses to glucose and bypass protein, this time by using another approach in which glucose was continuously administered into the duodenum; Merino x Border Leicester lambs (initially 19-25 kg) were given ad Zibitton a diet of oaten chaff and sugar (50:50) with 4% urea, and minerals. Catheters were implanted permanently into the duodenum. TWO groups of 12 lambs were used. One group received 6% fishmeal in the above diet; the other group was not given fishmeal. Within each group, 6 animals received glucose (80 g in 200 ml per day) by continuous infusion into the duodenum, and the other 6 were infused with 200 ml/day isotonic saline. The infusions were maintained throughout a growth trial lasting 6 weeks. The results are given in Table 1. TABLE 1. Effect of glucose infusion on feed intake, growth rate and feed conversion ratio of lambs. Continuous infusion of glucose into the duodenum increased growth rate of lambs and improved the feed conversion ratio on diets containing 0 or 6% fishmeal. The results indicate that glucose can increase the efficiency of utilisation of nutrients. When considered in conjunction with the earlier studies, the results also suggest that increased glucose availability may spare the deamination of amino acids and thus increase the efficiency of utilisation of protein by the animal. KEMPTON, T.J., HILL, M.K. and LENG, R.A. (1978). Aust.Soc.Anim.Prod.12: * Department of Biochemistry and Nutrition, University of New England, Armidale, N.S.W. 2351. #Present Address: Cyprus Agricultural Research Institute, Nicosia, Cyprus 134.
