Symposia and Oral Sessions

This study determined the availability of glycerol as indicator of energy status of broiler chicks during hatch, and the behavior of chicks subjected to three fasting times with reference to production standards. Chicks originating from 31 and 54 week-old Ross breeder flocks were utilized. Samples of liver were taken from chicks during the following time periods: pipping of eggshell, wet hatch, dry hatch, and 2.5, 12 and 24 hours post-hatch. Blood was also collected during each phase with the exception of the pipping. The serum samples were used to measure the concentration of glucose, cholesterol and triacilglycerides by COBAS Mira Roche® Analyzer. Liver samples were used to evaluate the quantity of free glycerol using the technique of O. Wieland.A total of 1260 chicks from each age of breeder flock were utilized for the study. Chicks from each source flock were separated into groups of 140 birds per treatment with 3 replications, and the fasting periods of 2.5, 12 and 24 hours post-hatch were evaluated. The growing period was continued through 49 days of age. Study results revealed that chicks originating from the younger source flock had a lower concentration of glycerol when correlated with the relative weight of the liver and the quantity of yolk. Serum glucose indicated that the energy reserves are at their lowest levels before the first administration of feed.Serum cholesterol levels were elevated due to the yolk absorption, and during hatch there was a high percentage of cholesterol esters. For triacylglycerides and glucose, there was a difference of p<0.05 between the chicks originating from the two source groups of breeder hens. The production results (body weight, consumption, feed conversion ratio) did not present a p<0.05 for any of the fasting time periods. The administration of early feeding caused benefits with respect to yolk absorption, weight of chicks at one-week of age. Nevertheless, when performance was actually measured in this study, improved performance due to early feeding was not detected.While early feeding caused better utilization of yolk and nutrients, pre-placement fasting did not negatively affect performance in this study.