This study aimed to examine the effect of methionine and/or betaine supplementation on bone measurements, some blood parameters, fatty acid differentiation and histological examination of broilers that fed low protein diets. A total numbers of 180 one day old unsexed Hubbard boiler chicks were divided into six treatments (30 birds each). Each treatment contained 3 replicates of 10 birds. Two levels of dietary crude protein (recommended D1) control diet, and 2% crude protein (D2), treatment diets (T1-T5) and DL-methionine (MET), or betaine (BET), were added in experimental treatment diets as follows:
1- Control; Chicks were fed control diet (D1)
2- T1: Chicks were fed low protein diet, 2% crude protein (D2)
3- T2: Chicks were fed D2 + 100% MET
4- T3: Chicks were fed D2 + 50% MET + 50% BET
5- T4: Chicks were fed D2 + 25% MET + 75% BET
6- T5: Chicks were fed D2 + 100% BET
All diets (control and T1-5) were equal in lysine % and MET add in the T2 diet up to control diet.
The results indicated that:
1- Tibia length was significantly affected by treatments and chicks fed (T2) diet gave the lowest significant values compared with control group.
2- Blood parameters showed insignificant figures in most parameters. However, AST activity had significant different and the best values were for chicks that fed on T4 compared to other treatments and control.
3- The saturation to unsaturation ratios were improved by betaine and methionine supplementation compared to control group.
4- Liver histology showed improvement for birds that fed betaine and methionine compared with control group.
It could be concluded that betaine and methionine have improved bird's health without any adverse effect on liver and these results obviously clear by blood determination. Therefore, MET and BET supplementation has been recommended in low-protein broiler diets without any adverse effect on bird's health.