Optimization of dietary energy intake to minimize egg production during market crises in White Leghorn laying hens

Abstract

Two feeding trials were conducted to stall the egg production (EP) in laying hens during a lean phase of the market demand for eggs through dietary modulations. For this, 1,000 and 1,200 commercial White Leghorn laying hens (BV 300, Babcock) of 71 and 81 weeks of age (experiments 1 and 2, respectively) were divided into five groups, each with ten and twelve replicates (20 birds in each), respectively. The birds were housed in 4-bird colony cage (45.7 × 35.6 × 43.2 cm @ 542 cm²/bird) and five cages in a row were considered as a replicate and reared under uniform management conditions in an open-sided elevated platform poultry house and provided 16 h of light/day throughout the study period. A control diet (CD) with 2625 kcal/kg metabolizable energy (ME) and 14.3 % crude protein (CP) and a test diet (TD) with 9.35 % CP and 2935 kcal/kg ME were prepared. The CD was fed ad libitum to the control group, and the other four groups were fed the TD employing quantitative restriction so as to provide 4 different intakes of ME (194, 204, 214, and 224 kcal/b/d) in Experiment 1 for a duration of 5 weeks from 71 to 76 weeks of age. Similarly, in Experiment 2, TD was fed in restricted quantities so as to restrict the ME intake to 158, 162, 175, and 184 kcal/b/d from 81 to 85 weeks of age, while the control group received ad libitum feed intake (FI). After the energy restriction phase, all the groups were offered CD ad libitum (77-80 and 86-91 weeks of age, respectively, in experiments 1 and 2). A significant decrease in EP (33.15 % and 5.05 % in exp-1 and 2, respectively), FI, body weight and egg weight were noticed during the energy restriction phase in the lowest energy-fed group (194 and 158 kcal/b/d, respectively, in the Experiments 1 and 2). The EP reached nearly zero percent with minimal body weight loss (52.64 g in 5 weeks) in Experiment 2. A significant increase in EP was noticed in energy-restricted groups on resumption of ad libitum feeding of CD. The FE was improved during the ad libitum recovery phase in energy-restricted groups. There was no significant variation in egg quality traits after returning to the CD. Some anti-oxidant variables (lipid peroxidation and activity of superoxide dismutase) exhibited a positive response to energy restriction and subsequent ad libitum feeding of the CD. Based on the results, it can be concluded that in WL laying hens (81-91 weeks of age), the energy restriction to 158 kcal/b/d for five weeks can be adopted as a less stressful method for cessation of EP to nearly zero percent, and resumption of ad libitum feeding of the CD will increase EP and reduce serum oxidative parameters within four weeks as compared to the pre-restriction phase without affecting egg quality and humoral immunity.