Broiler breeders utilise body lipid as an energy source

Abstract

________________________________________________________________________________ AbstractThe study was conducted to determine the extent to which broiler breeder hens could make use of excess body lipid reserves as a means of maintaining laying performance. The experiment was divided into two phases. In the first phase, the birds aged 37 weeks were allocated one of four daily allowances: 160, 175, 190 or 205 g of a commercial broiler breeder feed for a period of four weeks in order to achieve four levels of fatness in the hens. During the second phase, also lasting four weeks, the birds were given a high protein, low energy feed at three rates of allocation (120, 100 or 80 g/hen d). Performance was higher over the final two weeks of Phase 2 when birds were fed 120 g/d in this period, with production tending to decrease as allocations increased in Phase 1, although this was not significant. The same pattern of response was seen in birds given 100 g/d in the second phase of the trial, i.e. excessive lipid reserves tended to be detrimental to performance in these two treatments. However, where 80 g was allocated daily in Phase 2 this was clearly insufficient to sustain performance, but in this case egg production was considerably higher in birds that had been given larger amounts of food in Phase 1, and which could therefore draw on body lipid reserves as a source of energy. Rate of lay increased by 3.5% and egg output by 4.0 g/d for every additional 10 g of food given in Phase 1, as a result of lipid reserves having been utilised when daily food intake was severely depressed. Egg weight was not affected by any of the feed allocations until the last two weeks of the trial when birds fed 80 g/d started laying smaller eggs. Broiler breeders are capable of maintaining their egg production for short periods at an energy intake that is much lower than is recommended and this has implications when modelling the effect of food composition on performance of broiler breeder hens. ________________________________________________________________________________

Partitioning the efficiency of utilization of amino acids in growing broilers: Multiple linear regression and multivariate approaches

“…In this study, the maintenance was expressed in protein unit, as it corrected for growing animals, because it accounts for the maturity degree of protein ( u ), which is the relation of protein weight at a specific age by the mature protein weight. Furthermore, AA are not required for lipid reserves and considering that the amount of lipid might change among individuals [24] it is reasonable to choose body protein as a scale for maintenance calculation.…”

Dynamics of Growth and Egg Traits in Three Dietary Balanced Protein Scenarios Applied for Laying Hens

“…After the cited ages, the laying hens mobilize body fat, possible to maintain egg production, especially after 82 w-old, when the dietary metabolizable energy was reduced, as recommended by the guideline. Nonis and Gous [ 43 ] demonstrated that broiler breeders produce energy from body lipid if they are allowed to do it so, even though the concentration of dietary energy is above requirement, by regulating their feed intake. Similarly, Caldas et al [ 44 ] observed a reduction in broiler breeders fat at the end of egg production phase.…”

Broiler breeder nutrition affects chick quality and offspring performance : Fat or lean or in-between?

“…also observed a decrease in fat mass after peak production. Two potential mechanisms might be involved in the decrease in fat mass; 1) body fat is mobilized to support yolk fat or egg (Nonis and Gous, 2012) production or 2) body fat is mobilized to fulfill energy requirements for basic daily protein retention as breeders have not reached their somatically mature weight yet . Breeders fed the 96% AME n diet required a relative high feed intake to achieve pairgaining , where the surplus of nutrients were deposited as fat.…”