Effect of Dietary Protein Levels and Strain on carcass characteristics of Heat Stressed Broiler Chicks (original) (raw)
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Revista Brasileira de Zootecnia, 2013
This study was conducted to verify the effects of dietary crude protein reduction on growth and carcass performance of 22-42-day-old broilers reared under different temperatures. Treatments were set up in a five by two factorial arrangement, with five crude protein levels (220, 210, 200, 190 and 184 g/kg) and two temperatures (21.6 and 32.2 o C). Diets were isocaloric and essential amino acid-to-lysine ratio was maintained constant in all treatments. There was no interaction between crude protein reduction and environmental temperature for any of the parameters evaluated. Crude protein had no influence on feed intake. Nevertheless, weight gain and feed conversion ratio were linearly influenced by crude protein reduction. Worse performance was also observed in birds exposed to heat stress as compared with birds kept under thermoneutral temperature. There was no effect of crude protein reduction on breast and legs. Birds kept under heat stress had lower breast yield and higher leg yield as compared with broilers reared at 21.6 o C. Any crude protein reduction in the range of 220 to 184 g/kg for 22 to 42-day-old broilers has a negative effect on their performance. Heat stress worsens broiler performance and breast yield.
Agriculture and Biology Journal of North America, 2010
This experiment was conducted on three hundred unsexed day-old Arbor acre strains of broiler chicks for 56 days. The birds were divided into 4 dietary groups with 3 replications of 25 birds each. The diets contained 20, 15, 10 and 5%, respectively of rice offal (RO) being replaced by 0, 5, 10 and 15%, respectively of cashew nut reject meal (CNM). The data obtained were subjected to one-way analysis of variance. Significant (P<0.05) differences were observed in the mean weekly body temperature of the birds. The highest temperature of 41.1 0 C was recorded in diet 3 (10% RO and 10% CNM). Reduced digestibility of nutrients was observed in diet 4 (5% RO and 15%CNM). Reduction in dietary fibre content and increased energy density of the diet resulted in improved performance of the birds in spite of marginal rise in body temperature of the birds. The lowest feed intake (5550g) was obtained in diet 3 with the highest birds' body temperature. Highest weight gain (1790g), best protein efficiency of 1.64, comparably (P>0.05) best feed: gain of 3.27 and lowest mortality (2.90%) were obtained in diet 4 (5% RO and 15%CNM). The body temperature of 41.1 0 C obtained in diet 3 (10% RO and 10% CNM) resulted in the highest (37%) PCV value. The Hb, WBC and RBC values of the blood were also highest at this temperature. The total protein was significantly (P<0.05) influenced by increasing CNM inclusion in the diets. Carcass characteristics were statistically similar (P>0.05) across the treatment groups except in the abdominal fat which was significantly (P<0.05) lowest in diet 1 (control). The carcass yield ranged from 76.52 to 79.49% with diets 4 (5% RO and 15%CNM) and 2 (15% RO and 5% CNM) having the highest and lowest values, respectively. It was concluded that the nutritional intervention of using CNM to replace RO up to 15% in the diets of broiler chickens did not significantly reduce the bird's body temperature though, there were marked improvements in the performance of the birds.
Brazilian Journal of Poultry Science, 2007
In order to evaluate the effects of broiler genotype and of heat exposure on performance, carcass characteristics, and protein and fat accretion, six hundred one-day-old male broilers were randomly assigned in a 2 x 3 factorial arrangement, according to the following factors: genetic group (selected and non-selected broilers) and pair-feeding scheme (Ad32 - reared under heat stress and fed ad libitum; Ad23 - reared at thermoneutrality and fed ad libitum; Pf23 - reared at thermoneutrality and pair fed with Ad32), with a total of six treatments with four replicates of 25 birds each. Independent of pair-feeding scheme, selected broilers showed better feed conversion, higher carcass yield, and lower abdominal fat deposition rate. However, as compared to non-selected broilers, they reduced more intensively feed intake when heat exposed, which promoted significant breast-yield decrease, and more pronounced changes on carcass chemical composition. These findings allows concluding that, in both genetic groups, both environmental temperature and feed-intake restriction influence abdominal fat deposition rate and other carcass characteristics; however, the impact of heat exposure on broiler performance is more noticeable on the selected line.
Effect of varying dietary energy and protein on broiler performance in hot climate
Animal Feed Science and Technology, 2008
The experiment was conducted to evaluate the effect of varying dietary metabolizable energy (ME) and crude protein (CP) concentrations on broiler performance during hot summer conditions. One day old straight-run (0.50 male and 0.50 female) Starbro broiler chicks (n = 600) were randomly divided into 30 experimental units of 20 chicks each. Two levels of dietary ME (12.13 and 12.55 MJ/kg) and three levels of dietary CP (190, 210 and 230 g/kg) were used in a 2 × 3 factorial arrangement giving six dietary treatments. Level of essential amino acids were maintained in all the diets by supplementing low CP diets with crystalline amino acids. Each of the experimental diets was offered to five replicates from hatching to 28 d of age. At the end of the experiment, two birds from each replicate were randomly selected for data on dressing yield, breast meat yield, abdominal fat, and liver and gizzard weights. Increasing dietary ME significantly increased the BW gain, abdominal fat and liver weights, and protein and fat contents of the carcass whereas the dry matter of carcass was reduced by increasing dietary ME. Dietary CP had quadratic effects on BW gain, F:G, carcass weight, and dry matter and protein contents of the meat. Breast weight and fat contents of meat increased linearly with increasing CP of the diets. The low CP diets (i.e., 190 g/kg) at high ME (i.e., 12.55 MJ/kg) increased * Corresponding author at: et al. / Animal Feed Science and Technology 146 (2008) 302-312 303 the BW gain, feed intake, carcass weight and improved F:G. However, lowest F:G was observed in birds fed 210 g CP and 12.13 MJ ME/kg of diet. Protein and fat contents of the carcass were increased in birds fed on diets having high CP and ME whereas dry matter contents of meat improved with high CP and low ME diets. The results of the trial showed a correlation between dietary CP and ME and hence the optimal value for one cannot be predicted without considering the other. Briefly, low CP with high ME diets improved the overall performance when environmental temperature ranged from 32 to 39 • C.
Influence of broiler strain cross and dietary protein on the performance of broilers
Poultry Science, 1998
The purpose of this experiment was to quantify the responses of two broiler strain crosses to different dietary protein levels on performance and carcass yields. Day-old broiler chicks from a high-yield strain cross (Ross × Ross 208) and a fast-growing strain cross (Peterson × Arbor Acres) were placed in floor pens on fresh pine shavings. All birds were fed a 23% CP starter for the first 18 d. During Days 18 to 53, birds were fed either 16, 20, or 24% CP diets (3,200 kcal ME/ kg). At 53 d of age, significant differences (P < 0.05) were noted in the performance of the strains. Overall, Ross × Ross birds had higher body weights (3.29 vs 3.10 kg), higher feed intakes (6.40 vs 6.11 kg), and higher carcass yields (72.51 vs 71.17%), although the differences were dependent on dietary protein levels. Strain cross had no significant effect on feed conversion (1.95 g feed: g gain vs 1.97 g:g). Results indicated that both strain cross and protein level had effects on body weight and feed intake, and there were significant strain cross by protein level interactions for body weight and carcass weight. Increasing dietary protein level increased body weights more for the Ross × Ross 208 than for the Peterson × Arbor Acres broilers. Feed conversion was indirectly proportional to dietary protein level, but was not affected by strain cross. Percentage carcass yield was greatly affected by strain (P < 0.0001), but protein level had no significant effect (P = 0.68). The significant interactions indicate that different strain crosses should have different feeding programs to maximize profitability.
The present study was carried out during summer season to examine the response of two broilers strains (RS = Ross 308 and CB = Cobb 500) to protein concentrate removal from finisher diet (28-42 d of age) on performance and carcass parameters. On day 28 of age, a total of 960 birds of two strains were randomly assigned on 32 replicates (16 replicates for each strains) of 30 chicks per replicate. Each replicate consist of 15 males and 15 females for each strain which was distinguished by phenotype. Tow finisher dietary treatments were: (1) the basal diet with protein concentrate supplementation; (2) the basal diet without protein concentrate supplementation were fed for both strains. Body weight (BW) and gain (BWG), feed consumption, feed conversion ratio, mortality and carcass parameters were examined. Results showed that the RS strain achieved greater BW, weight gain and feed consumption than CB strain. While, feed conversion ratio and mortality was not affected by strain. Regardless of strain, results showed that removal of protein concentrate (PC) from finisher ration caused reduction in BW at 35 days and 42 days of age and BWG. The reduction in BWG due to PC removing was 8.15% for 7 days and 18.02% for 14 days. As well as, reduction also occurred in feed consumption and feed conversion ratio from 28 to 42 days of age. In contrast, omitting PC from finisher diets had no effect on carcass yield, breast and thigh meat and abdominal fat pad. In conclusion, the results from this study suggest that 14 days withdrawal of protein concentrate prior marketing have adversely negative effect on performance but not on carcass parameters of both strains of broilers during hot climate.
Effect of Environmental Heat Stress on Performance and Carcass Yield of Broiler Chicks
World’s Veterinary Journal , 2019
Environmental heat stress is one of the most challenging conditions which have adverse effect on the poultry industry. Broiler chickens are sensitive to heat stress mainly due to not having sweat glands. The current study was conducted to observe the effect of heat stress on performance of Ross-308 broiler chickens. 1600 Ross-308 broiler day old chicks were obtained from local hatchery and randomly divided into two groups, the heat stress group A (n=800) and heat free group B (n=800). Group A was reared in high temperature (101 0 F) whereas group B was reared in ideal temperature. To evaluate the physiological stress indicators blood glucose levels and total blood cell count were checked on day 21 and 28. The parameters observed were; feed intake, body weight gain, feed conversion ratio, water intake and carcass yield. The results indicated that feed intake, weight gain, water intake, feed conversion ratio and carcass yield were significantly higher in group B compared to group A. It was concluded that heat stress has deleterious effect over the performance of broiler Ross-308 chicken.
Impact of Heat Stress on Growth Performance and Carcass Traits in Some Broiler Chickens
Arab Universities Journal of Agricultural Sciences, 2020
Environmental heat stress is one of the most challenging conditions in the world which have adverse impact on the industry of poultry. Broiler chicken strains are delicate to heat stress primarily due to not having sweat glands. The current study was aimed to investigate the effects of heat stress exposed on growth performance and Bio-physiological characteristics for (Cobb, Hubbard and Arbor Acres broiler hybrids) under the summer season when environmental conditions of Egypt were revealed. A total of three hundred one day old (one hundred birds from each hybrid) at one day of age were brooding under the same conditions of water, diet consumed, breeding system, vaccines and medications used during the period birds life even slaughtering age. The three strains were randomly divided into twelve groups (three strains "Cobb, Hubbard and Arbor Acres" X two treatments "control group and heat exposed group" X two replicates X twenty five chicks).The degrees of environmental temperature and relative humidity during housing are (Environmental temperature = 32°±2 Celsius degree, Relative humidity = 50±5 percentage) for control group and (Environmental temperature =40°±2 Celsius degree, Relative humidity= 20±5 percentage) for the heat stressed group. The body weight, body weight gain, edible parts of carcass (carcass, thigh, drum, breast muscles and giblets weight) and inedible parts of carcass (blood, feathers, head and legs weight) were recorded to heat stressed group and control group. Lymphatic organs such as spleen, thymus and bursa weight were measured also. The last results concluded that the Cobb strain showed the best growth performance and carcass characteristics under heat stress condition, while the Arbor Acres strain considered the best strain which didn't effected a lot in their rectal temperature such another strains with heat exposure. The Arbor Acres strain for each group (control and treated) have the highest viability. The control group and Hubbard strain showed an increase in bursa weight compared to heat exposed group and another strains. It was concluded that the Cobb strain has the best performance under heat stress comparing to the other strains broiler chicken.