Effect of Qualitative and Quantitative Feed Restriction on Growth Performance and Immune Function in Broiler Chickens

Abstract

The current study was conducted to investigate the effect of early feed restriction (FR, 8 to 14 d of age) on growth performance and immune function in broiler chickens. Birds were fed corresponding diets from 3 to 35 d of age, which consisted of three phases: starter (3 to 7 d of age), FR (8 to 14 d of age) and re-alimentation (15 to 35 d of age) phases. During the FR period, each group of birds was fed the basal diet ad libitum (CON), 85% (EN85) and 70% (EN70) of lower calorie diet ad libitum (qualitative FR), and 85% (FI85) and 70% (FI70) of voluntary intake on a daily basis (quantitative FR). As a result, there was no statistical difference in weight gain, feed intake and feed conversion ratio between the CON and quantitative or qualitative FR groups during the entire (3 to 35 d) periods. In particular, the EN85 group resulted in a significant (p<0.05) increase in weight gain compared with the EN70, FI85 and FI70 groups. Plasma total protein and albumin at 14 d of age (during FR) were significantly (p<0.05) lower in the quantitative and qualitative FR groups, but these parameters at 35 d of age (after re-alimentation) were higher (p<0.05) in the EN85 and EN70 groups than in the CON group. Plasma IgG level was unaffected by dietary FR procedure. In cytokines, there was no significant difference in the expression of lymphocytic IL-4 and IFN-γ at 14 d of age between the FR and the CON groups, whereas lymphocytic IL-6 and iNOS expression were significantly (p<0.05) lower in FI85 and FI70 groups. Moreover, lymphocytic iNOS was also significantly (p<0.05) lower in birds fed qualitative and quantitative diets compared with those fed ad libitum. In the thymus, IL-4 expression was higher (p<0.05) in FI85 and FI70 groups, whereas IL-6 expression was lower (p<0.05) in the FI85 and FI70 groups than in the CON group. Thymic iNOS was significantly (p<0.05) lower in birds fed qualitatively and quantitatively restricted diets compared with those fed ad libitum. At 35 d of age, there was no difference in the expression of IL-4, IL-6 and IFN-γ of lymphocytes and thymus between the FR and CON groups. In conclusion, 85% of quantitative and qualitative FR would have a beneficial effect on the expression of some cytokines including IL-4 and iNOS without change in growth performance of birds.

Thyroid Hormone and Blood Metabolites Concentrations of Broiler Chickens Subjected to Feeding Time Restriction

“…The importance of such reserve in resisting the stresses of caloric restriction (Leveille & Sauberlich, 1961). Contrary to this finding, Jang et al (2009) found that total protein concentrations of broiler subjected to feed restrictions (70% ad libitum) from 8-14 d of age was lower than the control at 14 d of age (1.96 vs 3.26 g/dl), however, it had similar level (2.76 vs 2.12 g/dl) at the end realimentation period (35 d of age). This finding indicate that feeding time restriction had lower intensity of feed restriction, so that there was not any change reserve protein during feed restriction.…”

“…These results in line with ElFiky et al (2008) that feed availability for 4 h/d with two periods of 2 h (7:00 to 9:00 and 12:00 to 14:00) decreased plasma albumin concentration of broiler (2.10 vs 2.63 g/dl) at 35 d of age. The other report, Jang et al (2009) found that plasma albumin concentrations of broiler subjected to feed restrictions (70% ad libitum) from 8-14 d of age is lower than the control at 14 d of age (0.82 vs 1.26 g/dl). Nevertheless, these findings differ with Demir et al (2004) that feed withdrawal for 16 h/d from 13-21 d of age was not influence plasma albumin of broilers at the end feed restriction (123 vs 117 g/dl).…”

“…Thyroid hormone concentration is closely related to protein synthesis and energy production (Smith et al, 2002), and that relate to the performance of growth and changes in energy metabolism of broilers (Zhan et al, 2007). The other research, Jang et al (2009) reported that the quantitative and qualitative feed restrictions during 7 d from 8-14 d decreased plasma protein and albumin concentrations of broiler chickens. However, Boostani et al (2010) reported that feed availability for 8 h/d from 7-21 d did not influence plasma proteins and albumin concentrations of broiler chickens.…”

“…These situations most commonly occur with broilers that consume feed ad libitum. In addition, under feeding ad libitum, some chicks may develop a habit of feed over consumption (Svihus & Hetland, 2001), and this condition does not always mean that broiler chicks are good status of health and welfare (Jang et al, 2009). Therefore, restriction on feed availability through feeding time restriction may be a solution to these problems.…”

Digestive Enzymatic Responses of Chickens Feed-restricted and Refed as Affected by Age

“…Most studies agree that gastrointestinal organ weight is reduced by feed restriction but is recovered by refeeding. Realimentation after feed restriction can improve feed efficiency and compensatory growth (Jang et al, 2009), and it is possible that this response can be attributed to the recovery of enzyme activity. Therefore, it is imperative to know the physiological changes that underlie feed restriction and subsequent realimentation to better understand animal nutrition and health.…”