Relationship of dietary crude protein level and digestible lysine: calorie ratio on laying performance of aged laying hens
2024
Atienza, F.T. Jr
The study was conducted to determine the effect of different levels of CP and SD Lys: calorie ratio on the laying performance of aged laying hens. A total of 192 122-week-old laying hens were randomly assigned to one of the treatments in RCBD wherein weight and pen location are the main blocking factors. A 2 x 2 factorial treatments were designated with two levels of CP: 16.40% and 14.40% and two SD Lys: calorie ratios: 2.82 and 3.16 g/Mcal were used in the diet. There were 8 replicates each treatment with 2 cages per replicate. Laying performance, egg quality, nutrient digestibility and economic parameters were measured. Result showed significant interaction (P0.05) between dietary CP and SD Lys: calorie ratio in egg weight (EW), egg classification, albumen height (AH), Haugh unit (HU), shell weight (SW), yolk (YP), and albumen percentages (AP). No significant difference between treatments in EW and EM, but Standard CP with high SD Lys:cal ratio has the highest (P0.05) percentage of jumbo eggs. It also had the highest (P0.05) SW. On the other hand, AP, AH, and HU were highest (P0.05) in low CP with standard ratio, and lowest (P0.05) in standard CP with standard ratio. This result is inversely related to YP. On the main effects, low CP obtained higher (P0.05) yolk color index (YCI), AME and DM digestibility and tends to have better N utilization efficiency (NUE). On the other hand, it had lower (P0.05) YW and YP, For the SD lys:cal ratio, Y W and YCI were higher (P0.05) in increased ratio, but with depressed (P0.05) value on NUE and AME as compared with standard. Low CP and increased ratio generally obtained lower (P0.05) egg to feed cost ratio and margin over feed cost. But with Gly addition, low CP diets obtained better economic performance. Based on the results of the current study, different CP and SD Lys: calorie ratios have interactive and varying effects on the laying performance of the aged laying hens.
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