Growth-Associated Traits in Parental and F1 Populations of Chickens Under Different Feeding Programs

Abstract

Growth traits and digestive enzyme activities were compared in parental lines and F1 crosses under ad libitum and alternate-day feeding. Responses to the feeding regimens were, in general, dependent on the background genome and age. Population by feeding regimen interactions were more prevalent for growth traits than for enzymatic activities. Although chickens adapted morphologically and physiologically to the particular feeding regimen to which they were exposed, the degree of adaptation was population dependent. Moreover, a line of White Leghorns differed considerably in response compared to a line of White Rocks selected for low body weight, demonstrating that weight is primarily a result of metabolic and behavioral processes rather than the determiner of those processes.

Weight of internal organs and carcase yield of early food restricted broilers

“…Iilja et al (1985) reported that an increase in the size of the digestive organs improved the capacity of the chickens to ingest and digest food. Others (Nir et al, 1987;Katanbaf et al, 1989) have also shown that a greater weight and length of crop and oesophagus increases the capacity of these organs to retain and control the evacuation of food from the crop.…”

“…Differences in the response of chickens to restriction may be attributable to differences in feeding regimens and the strains of chickens used. Developmental patterns in chickens are influenced by their genetic background (Barbato et al, 1984;Pinchasov et al, 1985;Nir et al, 1987Nir et al, , 1993Katanbaf et al, 1989;Boa-Amponsem et al, 1991) but the genetic factors influencing the development of the supply organs which support the functions of the demand organs (e.g. feathers and muscles) can be modified by non-genetic management practices such as food restriction.…”

Effects of intensity and duration of quantitative restriction of feed on broiler performance

“…Similarly, other studies have shown that at the end of restricted period the average conversion rate of chickens fed for 5 days with 50% of requirements was significantly higher than that of controls (Lee and Leeson, 2001;Teimouri et al, 2005). These observations could be explained through increased absorption of available amino acids (Gous et al, 1977) or via increased synthesis of digestive enzymes during the food restriction period (Nir et al, 1987). Pinchasov et al (1993) showed that feeding regimens affect activity of proteolytic enzyme, so that trypsin activity in broilers under intermittent feeding increased compared to the chickens fed ad libitum.…”

Genotype, Feeding Regimen, and Diet Interactions in Meat Chickens.

“…Chickens develop morphological, anatomical, physiological, and behavioral characteristics that are population-dependent in response to different feeding regimens such as ad libitum, intermittent, and force-feeding (Barbato et al, 1984;Pinchasov et al, 1985;Nir et al, 1987). These feeding regimens allow for varying proportional differences in availability of energy.…”