Effect of feed restriction on the maintenance energy requirement of broiler breeders

Abstract

Objective: This study aimed to evaluate the effect of the ad libitum and restricted feeding regimen on fasting heat production (FHP) and body composition.Methods: Twelve Hubbard broilers breeders were selected with the same body weight and submitted in two feeding regimes: Restricted (T1) with feed intake of 150 g/bird/d and ad libitum (T2). The birds were randomly distributed on the treatments in two runs with three replications per treatment (per run). The birds were adapted to the feed regimens for ten days. After that, they were allocated in the open-circuit chambers and kept for three days for adaptation. On the last day, oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured by 30 h under fasting. The respiratory quotient (RQ) was calculated as the VCO2/VO2 ratio, and the heat production (HP) was obtained using the Brower equation (1985). The FHP was estimated throughout the plateau of HP 12 hours after the feed deprivation. The body composition was analyzed by dual-energy X-ray absorptiometry scanning at the end of each period. Data were analyzed for one-way analysis of variance using the Minitab software.Results: The daily feed intake was 30 g higher to T2 (p<0.01) than the T1. Also, the birds of the T2 had significatively (p<0.05) more oxygen consumption (+3.1 L/kg0.75/d) and CO2 production (+2.2 L/kg0.75/d). That resulted in a higher FHP 359±14 kJ/kg0.75/d for T2 than T1 296±17.23 kJ/kg0.75/d. In contrast, the RQ was not different between treatments, with an average of 0.77 for the fasting condition. In addition, protein and fat composition were not affected by the treatment, while a tendency (p<0.1) was shown to higher bone mineral content on the T1.Conclusion: The birds under ad libitum feeding had a higher maintenance energy requirement but their body composition was not affected compared to restricted feeding.

Comparative Analysis of the Growth Rate, Body Weight Gain, and Feed Conversion Ratio of Broilers Raised Under Ad Libitum and Restricted Feeding Programs

“…Furthermore, the data on feed intake confirmed that broilers provided with ad libitum feeding consumed consistently higher amounts of feed compared to those under restricted feeding. This finding is in line with expectations, as the ad libitum group had unlimited access to feed, whereas the restricted group had their feed intake limited by predetermined amounts 15 . Higher feed intake in the ad libitum group is expected to contribute to their superior growth rates.…”

Energy utilization and requirement of broiler breeders during the production phase

“…In this regard, reports have demonstrated the variation of FHP due to methodological or procedural approaches. For example, Teofilo et al (2022) found similar values (296 kJ/kg 0.75 *d) to those obtained here in a restricted-fed broiler breeder using the indirect calorimetry method.…”

“…The variations found are attributed to environmental factors such as floor production or cages that interfere with the energy cost of physical activity for floor-reared birds ( Sakomura et al, 2003 ). As mentioned by van der Klein et al, 2020 , Rabello et al (2004) , and Teofilo et al (2022) , the maintenance requirement is affected by factors like environmental temperature and feeding program (restricted or ad libitum) and have statistical implication when the feeding level is altered. Therefore, this method was questioned in other species ( Koong et al, 1985 ; de Lange et al, 2006 ; Labussière et al, 2011 ).…”

Effects of Metabolizable Energy Intake and Body-Weight Restriction on Layer Pullets: 1-Growth, Uniformity, and Efficiency

“…However, while similar BW can be achieved with different dietary ME levels, body composition might differ, especially when the ratio of other nutrients (crude protein and AA) is kept constant across the different dietary energy levels. Similarly to dietary energy, feed restriction tends to show higher feed efficiency due to decreased maintenance requirements and fat deposition [11,52]. Although no maintenance requirements and fat deposition results are presented in the present report, the greater feed efficiency in the restricted-fed compared to ad libitum-fed birds corroborates the results of the present study.…”

“…However, feed restriction programs might be helpful for optimal profit yield instead of optimal reproductive performance [10]. Restricted pullets have lower maintenance requirements, consuming less feed and being more efficient [11]. On the other hand, severe feed restriction during the rearing period can limit nutrient intake and decrease BW and egg production [12,13].…”