The Biochemical and Molecular Effects of Amnionic Nutrient Administration, "in Ovo Feeding" on Intestinal Development and Function and Carbohydrate Metabolism in Turkey Embryos and Poults.

Abstract

Unlike the mammalian embryo, the avian embryo has a finite amount of energy and nutrients for growth and development. In ovo feeding (IOF), the administration of exogenous nutrients into the amnion, may enhance egg nutriture and early growth performance by improving glycogen status and maturation and function of the gastrointestinal tract (GIT). This hypothesis was challenged by evaluating 5 IOF solutions in 2experiments. In experiment-1, IOF solutions were protein (EWP), HMB and carbohydrate (CHO). IOF treatments were arranged as a factorial arrangement of 2 levels EWP (0 and 18%), 2 levels HMB (0 and 0.1%). The CHO IOF solution (20% dextrin and 3% maltose) was evaluated for contrast. In experiment 2, IOF solutions were HMB, arginine (ARG), and EWP. Treatments were arranged as a factorial arrangement of 2 levels HMB (0 and 0.1%), 2 levels ARG (0 and 0.7%). EWP (18% EWP + 0.1% HMB + 0.7% ARG) was evaluated for contrast. At 23 d of incubation (23E) 1.5 ml of IOF solution was administered. Upon hatch, poults were provided feed and water ad libitum.

In experiment 1, body weights (BW) were determined at hatch, 3 and 7 d, and tissues were sampled for glycogen content of liver and muscle (PC). In experiment 2, BW were determined at hatch and 3, 7, 10, and 14 days and samples were taken to determine glycogen content of liver and PC, hepatic glucose-6-phoshatase (G6P) activity, and jejunal sucrase (S), maltase (M), and leucine aminopeptidase (LAP) activity. Additionally, S, M, LAP, SGLT-1 and Pept-1 expression levels were determined at 25E, hatch, 3, 7, and 14 days.

In experiment 2, poults of EWP, EWP +HMB and HMB alone weighed 6.0%, 2.7% and 3.3% more than the non-injected controls (C) at hatch, respectively (P<0.05), revealing a significant EWP X HMB interaction. Total hepatic glycogen (HG) was enhanced by the inclusion of EWP in the IOF solution at hatch (p<0.05), whereas total muscle glycogen was enhanced at 7 days by IOF HMB (p<0.05). When contrasting IOF solutions EWP, CHO and C, poults of EWP had the greatest HG reserves at hatch (p<.05), by 7 days, poults of EWP and CHO had higher HG reserves than C (p<0.05). Additionally, poults of CHO had enhanced total muscle glycogen stores in comparison to C; while poults of EWP had significantly less total muscle glycogen stores than C (p<0.05).

In experiment 2, all in ovo fed poults had 3-4% greater BW than C at hatch and the main effects of ARG and HMB responded independently (p<0.05). Poults of HMB + ARG had BW that were 10-11% greater than C at 10 and 14 days (p<0.05). At hatch, poults of ARG, HMB and ARG + HMB had an 84%, 78.7%, and 75% greater total hepatic glycogen than C (p<0.05), with greater hepatic G6P (p<0.05) activity and a significant ARG X HMB interaction on HG (total (mg), mg/g) and G6P activity (p<0.05).

Jejunal S and M activities were 3-fold greater in poults of ARG + HMB than all other treatments at 14 days (p<0.05). Jejunal LAP activity was improved by IOF HMB + ARG over C at 25E, hatch, 3-d and 14-d with a HMB X ARG effect (p<0.05). There was an HMB X ARG effect on jejunal Pept-1, SGLT-1 and SI expression levels at hatch, 3d, and 7 d (p<0.05). At hatch, Pept-1, SGLT-1 and SI jejunal expression was enhanced by IOF of HMB in comparison to C (p<0.05).

These studies demonstrate that IOF of HMB, ARG and proteins may enhance early growth by improving intestinal function and development, which may provide the nutrients and energy needed for more rapid growth.