Effects of timing and duration of feed restriction during rearing on reproductive characteristics in broiler breeder females

Abstract

The objective of this study was to determine whether there exists a critical period during rearing when restricted feeding of broiler breeder hens can be most beneficial on subsequent egg production. Broiler breeder pullets were subjected to combinations of either ad libitum or restricted feeding during three periods before sexual maturity. Body weight gain, feed intake, and egg production were recorded. Ovary and oviduct weights were noted at age of first oviposition. At 15 and 18 wk of age and at age of first oviposition, chicken luteinizing hormone releasing hormone-I (cLHRH-I) in the median eminence and the levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the pituitary and plasma were determined. The results demonstrated that alternation between ad libitum and restricted feeding during rearing changed the growth curves of the birds. Feed restriction from 7 to 15 wk followed by either ad libitum or restricted feeding led to improved reproductive performance, suggesting that long-term feed restriction may not be necessary to attain good reproductive performance. The birds restricted from 7 to 15 wk of age had higher proportional weights of ovary (> or = 1.7%) and oviduct (> or = 1.58%) at age of sexual maturity. The cLHRH-I levels in the median eminence and gonadotrophin contents in the pituitary followed that of growth in response to feeding levels and timing of feeding and could be related to the timing of the onset of lay. At age of first egg, all groups had similar levels of cLHRH-I, LH, and FSH. However, no clear effect of level of feed intake or time period of restriction could be observed for plasma LH or FSH concentrations.

Behavioural, Endocrine, and Metabolic Effects of Food Restriction in Broiler Breeder Hens

“…These values as well as food consumption correspond with values reported by other authors in AL, 2R and R broiler breeder chickens (Bruggeman et al 1998(Bruggeman et al , 1999. The Fig.…”

Slow and steady wins the race? No signs of reduced welfare in smaller broiler breeder hens at four weeks of age

“…These improvements in production traits do however come at a price for the parental chicken generation, the broiler breeders. The high growth rate of broilers is not only coupled to high rates of cardiovascular and skeletal pathologies, but also to reduced fertility due to follicular hypersensitivity to local growth factors (GFs), premature HPA axis maturation and obesity-induced lipotoxicity in ovarian tissues (Bruggeman et al 1999;Decuypere et al 2002;Chen et al 2006). To overcome these problems, broiler breeders are commonly reared under feed restriction regimes which may reach feeding levels as low as a third of ad libitum intake during the most intense periods (de Jong et al 2002).…”

Somatotrophic and thyroid hormones around the onset of lay in broiler breeders under different conditions

“…The age-related increasing trend in T 4 and decreasing GH levels from 2 to 22 weeks as found by Bruggeman et al (1997Bruggeman et al ( , 1999) was shown to be reversed during the transition period when birds are coming into lay; GH was rising again to levels of 100-150 ng/mL, like levels found in young animals, while T 4 was decreasing again to pre-puberty levels of 4-6 ng/mL. These age-dependent inverse changes are reflected in the significant negative correlation of 0.92 between T 4 and GH.…”

“…However, a recent study has described the influence of food restriction on plasma concentrations of growth hormone (GH), insulin-like growth factor I (IGF-I), triiodothyronine (T 3 ) and thyroxine (T 4 ) in the period before sexual maturity in three groups of broiler breeders fed different quantities of food (Bruggeman et al, 1997(Bruggeman et al, , 1998(Bruggeman et al, , 1999. To our knowledge, no studies exist that describe both metabolic hormones as well as hormones of the reproductive axis in long-term studies spanning the prepubertal period and the onset as well as peak of lay.…”