الفهرس 
Introduction
Effect of betaine levels on broiler chickensOnly 14 pages are availabe for public view
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Abstract
This study was carried out at the experimental Poultry Farm, Faculty of Agriculture, Sohag University, Egypt. It was designed to study the effect supplementation of different levels of betaine on broilers performance.
A total number of 375 Ross, one day -old were equally divided into five groups (75 birds/each) with three replicates (25birds/each) and classified as follows: In the first group, birds were fed a basal diet without any betaine supplementation and served as control group. While, birds in the 2nd, 3rd, 4th and 5th groups were fed the same diet and supplemented with betaine at different levels 100, 150, 200 and 250% i.e. 2, 3, 4 and 5kg betaine/1000 kg diet, respectively. All birds were daily exposed to cyclic heat stress (35◦C) from 8 AM to 4PM and then from 4PM to 7 AM, they were exposed to natural ambient temperature. Chicks in all groups were housed in partitioned litter floor; each of them with (200cm ×100 cm).
Each nest was used as a replicate (25chicks) of the treatment, provided with a feeder and one nipple for supplementing water. Feed and water were available ad-libitim throughout the experimental period.
All chicks were exposed to continuous lighting programs (24L: 0 D, 23 L: 1D, 22L: 2D, 21L: 3D) during 1, 2, 3 and 4 weeks as well as (21L: 3D) with 60 watt light density from incandescent source lamb at the height of 2.4 m from the floor up to the marketing age.
The results could be concluded as follow: -
1. Body weight:-
The results showed that the means of body weight for birds in the 100 and 150% groups were significantly higher than the control group by about 2.8 and 2.1% as well as 8.1, 4.1, respectively at the 1st and 6th weeks of age. Also, the means body weight for birds in the group at 100% betaine significantly higher than those of control group by about 1.9 % at the 4th week of age. However the means body weight for broilers in the 200% group was significantly higher than those to the control group by about 4.3% at the 6th week of age.
2. Body weight gain:-
The results showed that body weight gain of birds in the (100%) group was significantly higher than that of the control group by about 4.2% as well as 9 and 1.2%, respectively from one to 7days and from 21 to 28 days of age. However body weight gain for broilers in the 100, 150, 200, and 250% groups from 35 to 42 days of age were significantly higher than those of the control group by about 5.55, 2.90, 0.77 and 6.88%, respectively.
3. Feed consumption:-
The results showed that feed consumption for broilers in the 100, 150, 200 and 250% groups significantly decreased (P≤0.05) compared to the control group by about 0.47, 7.1, 4.4 and 2.9% as well as 4.2, 8.2, 7 and 6.8%, respectively during the period from one to 7days and from 7 to 14 days of age. Also, feed consumption in the 100, 150, 200 and 250% groups were significantly decreased (P≤0.05) compared to control group by about 12.1, 5.9, 11.4 and 5.3% as well as 11.7, 14.2, 12.7 and 14 %, respectively from14 to 21 days and from 21 to28 days of age.
4. Feed conversion ratio:-
The results showed that means of feed conversion ratio of birds in the 100,150, 200 and 250% groups significantly decreased (P≤0.05) compared to control group by about 6.1, 10.9, 7.4 and 4.1%, respectively during the period from one day old to 7 days of age.
5. Blood constitutions:-
The results showed that the serum albumin for birds in the 100, 150, 200 and 250% groups significantly increased (P≤0.05) compared to control group by about 26.2, 54.5, 26.2 and 89.5%, respectively.
6. Thermoregulatory responses: -
6.1. Rectal temperature:-
The results showed that rectal temperature for birds in the 100, 150, 200 and 250% groups significantly increased (P≤0.05) compared to the control group at 42 days of age by about 0.14, 1.5,1.4 and 1.6% , respectively, while, no significant effect was detected all over the experimental period.
6.2. Respiration rate:-
The results showed that respiration rate for birds in the (150%), (200%) and (250%) groups significantly increased (P≤0.05) compared to the control group by about 12.2, 16.9 and 18.5% as well as by about 6.5, 7.2 and 8.8%, respectively at the 14 and 21 days of age. Also, the rate was significantly increased at 42 days of age by about 13.9, 5.5and 10.2%, respectively.
7. Slaughter traits:-
The results showed that the percentage of heart for birds in the (100%), (150%), (200%) and (250%) groups significantly increased (P≤0.05) compared to the control group by about 7.5, 17.5, 17.5and 30%, respectively.
8. Chemical composition of meat:-
The results showed that no significant effects of betaine supplementations on moisture %, crude protein %, crude fat% , crude fiber % and crude ash % of meat of different groups supplemented with 100, 150, 200 and 250% betaine/kg diet compared to the control group.
Part 2: Effect of betaine levels, stocking density and their interaction on laying hens performance
This study was carried out at the Research Poultry Farm, Faculty of Agriculture, Sohag University, Egypt. It was designed to study the effect of betaine supplementation and stocking density on laying hens performance. This work was done during the period from 24 March to 24 Jun, 2014.
A total number of 144 laying hens of Lohaman LSL at 28 weeks of age were equally divided into four treatments (36 birds /each) with three densities (3,4 and 5 birds/ each) and three replicates for each density as follows: In the first group, chicks were fed the basal diet without any betaine supplementation and served as control group. While, chicks in the 2nd, 3rd and 4th groups were fed the same diet and supplemented with betaine at different levels 150, 200 and 250%, respectively. All birds were housed in battery cages. Each cage served as replicate and has a group of birds according to its dietary and density treatment. Each cage was provided with a feeder and one nipple for supplementing water. Feed and water were available ad libitim throughout the experimental period.
All birds were exposed to alighting program which followed a 24 hrs photoperiod 16L and 8D with 30 lax light density from incandescent source lamb at the height of 2 m from the floor.
The results could be summarized as follows: -
1. Productive performance: -
1.1. Body weight: -
1.1.a. Effect of betaine levels:-
The obtained findings showed that the body weight of laying hens treated with 200 and 250% betaine/kg diet groups were significantly decreased by about 2.12 and 4.6%, respectively at 32 weeks of age, While the corresponding value at 36 weeks of age in the treated groups significantly decreased by about 2.9, 6.4 and 6.3%, respectively than those of the control group.
1.1.b. Effect of stoking density: -
The body weight at all ages under different stocking density was not affected.
1.1.c. Effect of interaction:-
No significant effect was detected due to interaction between betaine and stocking density on body weight at 28 and 40 weeks of age, while it had a significant effect at 32 and 36 weeks of age, respectively.
1.2. Feed consumption:-
1.2.a. Effect of betaine levels:-
The daily feed consumption of laying hens treated with betaine supplementation at different levels was insignificantly affected at different ages.
1.2.b. Effect of stoking density: -
The daily feed consumption for laying hens at density 4 and 5 birds/cage was significantly decreased than those of 3 birds/cage thought different ages.
1.2.c. Effect of interaction: -
The daily feed consumption for laying hens at different ages was insignificantly effect due to interaction effect at different ages.
1.3. Feed conversation ratio:-
1.3.a. Effect of betaine levels:-
The feed conversation ratio for laying hens was insignificantly improved in treated groups than those that of the control group.
1.3.b. Effect of stoking density:
The feed conversion ratio at density 4 and 5 birds/cage were significantly decreased than those of the control group at all ages expect from 28 to 32 weeks of age were no significantly affected.
C.1.3.c. Effect of interaction: -
It had no significant effect on feed conversion ratio of laying hens due to interaction between betaine and stocking density at all ages.
1.4. Laying rate: -
Laying rate for laying hens was insignificantly affected due to betaine supplementation, stocking density and their interaction.
1.5. Egg weight: -
Egg weight for laying hens was insignificantly affected due to betaine supplementation, stocking density and their interaction.
1.6. Daily egg mass:-
Daily egg mass for laying hens was insignificantly affected due to betaine supplementation, stocking density and their interaction.
1.7. Egg quality of laying hens:-
1.7.1 Internal egg quality traits:-
1.7.1.a. Effect of betaine levels:-
The obtained results showed that the albumin high significantly increased (P≤0.05) in treated groups 150, 200 and 250%, However the yolk percentage significantly increased, but yolk color significantly decreased compared to control group.
1.7.1.b. Effect of stoking density:
The means of albumen height significantly increased (P≤0.05) at density 4 and 5 birds /cage of laying hens compared to density 3 birds/cage.
1.7.1.c. Effect of interaction:
The results showed that significantly increased on albumen height, albumen percentage, yolk height, yolk diameter and yolk color of laying hens due to interaction between betaine and density.
1.7. 2. External egg quality traits: -
1.7. 2.a. Effect of betaine levels:-
The results showed significantly increased (P≤0.05) in egg shape index in treated groups 150, 200 and 250%. However the egg specific gravity significantly increased in group 150%, and shell percentage significantly increased in 200 and 250%. At group 150% shell percentage significantly decreased compared to the control group.
1.7. 2.b. Effect of stoking density:
The means of egg shape index significantly increased (P≤0.05) at density 4, Specific gravity significantly decreased at 5 birds /cage of laying hens but specific gravity significantly increased at density 4 birds /cage compared to density 3 birds/cage.
1.7. 2.c. Effect of interaction:
The results showed that a significantly increased on specific gravity and shell percentage by interaction of laying hens.
8. Yolk analysis: -
1.8.a. Effect of betaine levels:-
The results showed significantly decreased in moisture percentage in treated groups 150, 200 and 250% by about 1.78, 15.60 and 18.12%, respectively. Crude protein significantly increased in groups 150 and 200% by about 5.52% and 8.87% but at 4th group (250%) significantly decreased by about 25.94% compared to control group. While the crude fat and crud ash percentages were insignificantly affected by betaine supplementation.
1.8.b. Effect of stoking density:-
The means of moister, crude protein, crude fat and crude ash percentages in laying hens were insignificantly affected by stocking density.
1.8.c. Effect of interaction: -
The results showed that a significant effect on crude protein, while no significant effect on the moisture, crude fat and crude ash percentage due to interaction of laying hens.
9. Blood constitutions:-
9.1.Blood hematology:-
1.9.1.a. Effect of betaine levels:-
The results showed that the heterophil percentage in group (250%) significantly increased (P≤0.05) by about 62.04%, but it significantly decreased at 150 and 200% by about 32.01and 13.05%, respectively compared to the control group.
The lymphocyte percentage at 200 and 250% significantly decreased by about 8.67 and 32.03%, respectively, while in group at 150% basophile cells significantly increased by about 10.3% compared to control group. The H/L ratio at group at 150% significantly decreased by about 31.9%, but at groups 200 and 250% H/L ratio significantly increased by about 4.25and 59.13%, respectively compared to control group While the corresponding values of red blood cells, eosinophil, basophile, monoycte cells and hemoglobin were not insignificantly affected.