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Abstracts Vol. 22 No. 2
INTERRELATIONSHIPS AMONG TRIIODOTHYRONINE (T3), ENERGY AND SEX ON NUTRITIONAL AND PHYSIOLOGICAL RESPONSES OF HEAT STRESSED BROILERS
M. A. Al Harthi; A. A. El-Deek; And B. L. Al-Harbi
Faculty of Meteorology Environment and Arid Land Agriculture, King Abdulaziz University, Saudi Arabia.
The objective of this work was to elucidate the impact of triiodothyronine hormone (T3) in relation to the concentration of metabolizable energy (ME) and sex on growth performance, body temperature, respiration rate, carcass characteristics and meat chemical composition of heat stressed broilers at (35±2C) during the day and (30±1C) during night, and average 58±4% relative humidity for 6 weeks period. Total of 180 males and180 females, 21-d old Lohman broiler chicks were assigned to 2 levels (0, and 0.5 ppm T3), and 3 levels of dietary metabolizable energy (3470, high; 2900, moderate; and 1760, low ME/kg) as well as sex. Thereby, there were 6 dietary treatments within each sex. Each treatment was replicated three times (10-broilers each), thus there were 30- broiler chicks/ treatment/sex. The experimental diets were iso-nitrogenous and met nutrient requirements of broilers (NRC, 1994). The experimental period was lasted from 21-42 d of age. The obtained results could be summarized as following:
Dietary supplementation with 0.5 ppm of T3 significantly (P<0.05) impaired growth by 8.3% and feed efficiency by 7.5%, while increased water intake by 2.04% and increased mortality rate of broilers by 141% over groups fed diets without T3 supplementation.
Feeding high ME diet improved growth by 41.6, and 4.5%, feed efficiency by 74.1, 11.9, when compared with either the low or intermediate ME level, respectively. Meanwhile, this accompanied with negative impact (P<0.05) of increasing ME on feed intake. Also, Increased ME level also significantly (P<0.05) increased mortality rate.
A significant interaction between T3 and ME on water intake was shown in which decreasing energy level increased water intake of broiler chicks fed on T3-supplemented diet, while feeding intermediate ME level decreased water intake of broilers fed on diets without T3 supplementation.
Cloaca and skin temperatures as well as respiration rate measured at 6.00 am were significantly (P<0.05) increased by 0.58, 1.15, and 1.12 %, respectively, when the diet was supplemented with 0.5 ppm of T3. Whereas this effect was diminished when the measurements were taken at 2.00 pm, except for respiration rate which remained significantly higher by 1.93%.
Feeding intermediate ME diet significantly (P<0.01) increased cloaca and skin temperatures compared with the low or the high ME diet, and had insignificant effect on respiration rate measured at 6.00 am. However, feeding high ME diet increased cloaca and skin temperatures compared with the low and the intermediate ME level when measured at 2.00 pm, whereas greater value of respiration rate was obtained with the group fed on intermediate ME level.
Respiration rate exhibited a significant (P<0.05) relationship between ME and T3, showing that increasing ME level in T3-supplemented birds had little effect on respiration rate, however, feeding intermediate or high ME diet to T3-unsupplemented group increased respiration rate by 7.2% for both groups.
Broilers fed on T3-supplemented diet had significantly lower weights of empty carcass, gizzard, wings, neck, back and thigh.
Feeding high ME diet significantly (P<0.01) increased dressing percentage, and weights of empty carcass, heart, liver, wings, abdominal fat, neck, back, breast and thigh when compared with either the intermediate or low ME diet.
Absolute weight of abdominal fat of T3-supplemented group fed on low ME diet was 22.04% lower than that of the intermediate or the high ME diet, whereas low energy diet had only 2.82 and 9.52% less abdominal fat than either the intermediate or high energy diet of T3-unsupplemented group, respectively.
No significant impacts of dietary T3 supplementation or sex on moisture, crude protein, fat and ash contents of skinless, boneless meat were noted. Dietary ME levels affected only moisture percentage of broiler meat.
It is concluded that adding T3 hormone to broiler diets raised under high environmental temperature could not serve to alleviate the adverse effect of heat stress on broiler growth and decreased feed efficiency, even negative impacts were shown. However, increasing energy level induced improvement in growth and feed efficiency. Meanwhile, no effect of T3 or energy or sex or the relationship among them was observed on chemical composition of broiler meat.
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RESPONSE OF BROILER PERFORMANCE TO DIETS CONTAINING HOT PEPPER, AND/OR FENUGREEK AT DIFFERENT METABOLIZABLE ENERGY LEVELS
O. El-Husseiny, S. M. Shalash*, and H. M. Azouz*
Ani. Prod. Dept., Fac. of Agric. Cairo Uni. Giza, Egypt.
* Ani. and Poult. Prod. Res. Inst., ARC, Ministry of Agric., Dokki, Egypt.
Two experiments were designed to study the effect of feeding broiler chicks on diets containing various levels (1, 1.5 and 2%) of local natural feed additives (hot pepper and fenugreek seeds), at different levels of metabolizable energies (3200, 3000 and 2800 Kcal/ Kg). The two experiments were only varied according to the protein content in the diets. A total of 270 week old-Hubbard broiler chicks were divided into 9 experimental groups of approximately similar body weight. Each group consisted of 3 replicates of 10 birds each. Each group was fed one of the nine experimental diets from 7 to 49 days of age in each experiment. The results obtained could be summarized as follows:
Chicks fed hot pepper diet had significantly (P<0.01) higher body weight, dressing % and digestion coefficients of CP, NFE, OM, NB, TDN and ME than those fed the control or fenugreek diets. Feeding hot pepper diets improved significantly (P<0.01) feed, protein and ME conversion. Chicks fed fenugreek diet had significantly (P<0.01) less body weight (exp. 2) and higher feed intake (exp. 1) than those fed the control diet. Moreover, the addition of either hot pepper or fenugreek seeds to broiler diets decreased significantly (P<0.01) abdominal fat %.
Final body weights and dressing % of birds fed 3000 Kcal ME/Kg were significantly (P<0.05) higher than those fed 2800 or 3200 Kcal ME/Kg. Decressing energy level significantly increased feed intake and digestion coefficient of CP and decreased abdominal fat%, total lipids, total cholestrol, glucose and digestion coefficient of EE, NFE and ME. However, increasing dietary energy level improved significantly (P<0.01) feed and protein conversion. In Experiment 2, energy conversion for high energy level diet was significantly (P<0.01) higher than medium and low energy level diet.
There was significant (P<0.05) interaction between source of local natural feed additives and energy levels on body weight, gain, feed and ME conversion, ME, total lipids, total cholesterol and glucose.
No histopathological alterations were detected on proventriculus, gizzard, liver and small intestine for chicks fed different levels of hot pepper. In general, hot pepper is a good source of local natural feed additives for broiler chicks.
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EFFECT OF DIFFERENT LEVELS OF AVAILABLE PHOSPHORUS AND MICROBIAL PHYTASE ON LAYING HEN PERFORMANCE AND EGG QUALITY
M. O. Abd Elsamee
Department of Animal Production, Fac.of Agriculture, Cairo University.
A total number of 216 Bovans White laying hens 21 weeks of age were randomly distributed into 9 treatments, each containing 24 hens in 3 replicates .Three levels of available phosphorus (AP) and three levels of microbial phytase were used to study the effect of different levels of AP and microbial phytase on laying hen performance, egg qualit, digestibility coefficients, minerals retention and economic efficiency of egg production. Levels of AP were 0.45 % (positive control), 0.30 % (medium control) and 0.15 % (negative control). Microbial phytase was added to the diets either containing medium or low levels of AP (0.30 and 0.15 %) at levels of 300, 400 and 500 FTU / Kg of the diet. Laying hens were kept in cleaned and fumigated cages of wire floored batteries in an open system house under similar conditions of management up to 40 weeks of age. Water and feed were offered ad-libitum under a total of 16 hours light / day regimen.
The overall results showed that feeding laying hens on diet containing the optimum level of AP (0.45 %) recorded significantly (P < 0.05) higher egg production and improved significantly feed conversion ratio compared with those fed diets either containing medium or low levels of AP (0.30 and 0.15 %). While , the average values of egg weight and feed intake were not affected by using different levels of AP.At the same time, supplemental phytase to laying hen diets improved significantly (P < 0.05) egg production , feed intake and feed conversion ratio . Feeding hens on diets either containing the optimum level of AP or low levels of AP with supplemental phytase improved significantly (P < 0.05) egg quality as measured by percentage of shell-less eggs and shell thickness values. While, there were no significant differences in Haugh unit values due to treatments. Also, using the optimum level of AP or adding phytase to laying hen diets containing low levels of AP improved significantly (P < 0.05) minerals retention and digestion coefficients of nutrients except for crude fiber. Mortality rate values were not affected by treatments. Economic efficiency values increased by feeding hens on diets either containing the optimum level of AP or those containing low levels of AP with supplemental microbial phytase . Accordingly, the results of this study showed that adding microbial phytase can reduce the AP level in the laying hen diets without adverse effects on laying hen performance, egg quality or economic efficiency.
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