JWSS - Journal of Water and Soil Science

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This experiment was carried out to determine the relationship of plasma triglycerides and carcass dry matter with abdominal fat. One of the problems of broiler is carcass fatness, especially abdominal fat due to rapid growth of broilers which is not the consumer preference. Six hundred one-day-old commercial broiler chicks (Lohman) were divided into 40 groups, 15 chicks per group. Each one of the 10 experimental diets, in which barley was substituted for corn at levels of 0, 5, 10, 20 and 40%, was fed to 4 groups of chicks for 56 days. All diets were isoenergetic and isonitrogenous. Rice hulls was used to make diets isoenergetic. At days 42, 49 and 56, one male and one female were selected from each pen and after blood sampling, the birds were killed, eviscerated and percentages of carcass and amount of abdominal fats were measured. Blood samples were used to determine plasma triglycerides, cholesterol and total lipids. The results showed that increasing abdominal fat reduced carcass moisture content. Correlation between abdominal fat and plasma triglycerides was positive and significant (p<0.05). Correlation between abdominal fat and carcass moisture was negative and significant (P<0.01). The regression equations indicated that abdominal fat can be estimated from plasma triglycerides and carcass moisture content. The equations also indicated that using several parameters for estimating abdominal fat is better than single parameter estimation.

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Two experiments were conducted to evaluate the nutritional value of millet and tallow for broiler chickens. In the first experiment, the nitrogen corrected apparent metabolizable energy (AMEn) of millet and tallow were determined by the method of Sibbald. In the second experiment, a 3×5 factorial experiment was designed to evaluate the effects of 3 levels of tallow and 5 levels of substitution of corn with millet in broiler diets. Animal fat was included in the diets at levels of 0%, 3% and 6% and millet was replaced for corn at levels of 0%, 25%, 50%, 75% and 100%. Each diet was tested in 4 replicates including 12 chicks per replicate. Live body weights, feed consumptions and feed conversion ratios were determined weekly for all replicates. The AMEn of unground, ground, screened and ground and tallow were 3260, 3204, 3237 and 8166 Kcall/kg, respectively. Replacement of corn by millet at all levels did not have any adverse effect on body weight, feed consumption and feed conversion ratio at 56th day of age. Body weights, feed consumptions and feed conversion ratios were significantly increased (p<0.05) with increasing animal fat. The results indicated that millet has high energy value and appears to be at least equal to corn in promoting weight gains in broiler chickens.

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In a completely randomized design, 600 commercial day old broiler chickens were used to study the possibility of replacing corn with barley. Each of 10 experimental diets in which corn was replaced with barley at levels of 0, 5, 10, 20 and 40 percent, with and without tallow, were given to 4 replicates of 15 chickens each. At 42, 49 and 56th days of age, one male and one female from each pen were killed. Body weight gain, feed intake and feed conversion ratio were not affected by different levels of barley at 42th day of age. Increasing the level of barley had not effect on body weight gain at 56th day of age. Feed conversion ratio improved slightly due to addition of 4% tallow to the diets containing different levels of barley. Abdominal fat was increased due to added tallow in males and females. Increasing slaughter age increased abdominal fat in both sexes. Difference in abdominal fat in females was more than males.

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A total of adult leghorn roosters and 360 day-old broiler chicks were used in two completely randomized experiment to evaluate metabolizable energy (ME) and feeding value of faba beans in broiler rations. In a factorial arrangement with 10 treatments and 3 replicates chicks were fed isonitrogenous rations containing either 0, 10, 20 or 30 percent of raw, cooked or dehulled faba beans for 8 weeks. Data from sibbald procedure showed cooking had no significant effect on energy value of beans, while dehulled beans had a significantly (p < 0.05) higher energy value. Final body weights at 8th week of age were unaffected due to processing of beans. No significant differences were observed in liver weight, abdominal fat or feed efficiency ratio due to processing and/or percentage of beans in the ration. Raw, whole beans significantly (p < 0.05) increased percentage and weight of pancreas compared to those that had consumed dehulled beans. This indicates that trypsin inhibitor is located in hulls. Cooked beans reduced pancreas size to normal, indicating destruction of inhibitor due to cooking. One interesting point is that the control group which consumed more soybean meal had a pancreas weight of 4.67 grams comparable to 4.83 grams of pancreas weights of chicks consuming raw, whole beans. This last fact indicates that soybean meals might not have received enough heat treatments during processing, which requires further investigation.

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Effect of different sources of fat on performance of broiler chicks was studied. Three hundred and thirty six chicks were divided into 42 groups of 8 chicks per group. Seven isoenergetic and isonitrogenous diets, mainly based on corn and soybean meal were prepared and fed. These treatments were as follows: corn + soybean meal + (5% tallow, 5% cotton seed crude oil, 5% cotton seed soapstock, 2.5% tallow + 2.5% crude oil, 2.5% tallow + 2.5% soapstock, or 2.5% crude oil + 2.5% soapstock). One control diet without any source of fat was also included. Results showed that average feed intake of diets with different sources of fat up to 56 days old, was not differed from control group. Different sources of fat and their combinations increased weight gain and improved feed conversion. But soapstock had no effect on performance. Added fats increased abdominal fat of chickens. Therefore, if is concluded that on the contrary to soapstock, tallow and crude oil enhanced performance of broiler chickens.

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Barley consumption is limited in broiler chicken diet due to their β. glucanas polysaccharide content. The application of synthetic enzymes in poultry diet can increase the barley content. The purpose of this experiment is to study the effect of enzyme supplement-β-glucanas on the performance of broiler chickens, percentage of abdominal fat, intestine weight and economic evaluation of production of one kilogram of meat in diets including different levels of barley and corn. Five hundred forty-one-day-old commercial broiler chickens (Arian) were divided into 45 groups, 12 chickens per group Each one of the 15 experimental diets, in which barley was substituted for corn at levels 0, 25, 50, 75 and 100% with 2 levels of enzymes (0.025 and 0.05%) was fed to 3 groups of chickens for 49 days. All diets were isoenergetic and isonitrogenous. Plant oil was used to make diets isoenergetic. The results showed that the rate of weight increase of broiler chickens decreased as each level of free enzyme barley was replaced at 0.83, 6.08, 12.9, 16.1 %, respectively. The weight gain of the chickens fed with diets including a large amount of barley and 0.05% enzyme didn’t have any significant difference (P < 0.01) with the control group. The chickens fed with diet including barley and 0.025% enzyme didn’t have any significant difference either (except at 75% and 100% barley replacements). Enzyme supplementary at 0.025% and 0.05% levels (especially at 0.05%) caused significant improvement (P < 0.01) in food consumption and feed conversion ratio of chickens fed with diets including barley. Analysing the carcass of these chickens showed that the enzyme used at both levels, especially at 0.05 %, caused a significant decrease (P < 0.01) in abdominal fat (3.62% vs. 4%). It was also seen that the weight of chickens fed with enzyme decreased significantly (P < 0.01) in comparison with chickens fed with free enzyme barley diets (9.57% vs. 14.81 %). The economic calculation results of producing meat in this experiment pointed out that using barley and corn caused reduction in production expenses. The general results of this study showed that barley with enzyme is a suitable replacement for enzyme and further that 0.05% level of enzyme is better than 0.025% level due to its performance and better economic results.

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In order to study the effects of Total Dissolved Solids (TDS) in water on the performance of broiler chickens, preliminary data were obtained on water resources of Isfahan Province. Complementary tests and analyses were also performed including physical, chemical and microbial ones. Six different water qualities based on TDS contents of less than 1000, 1000-2000, 2000-3000, 3000-4000, 4000-5000 and more than 5000 ppm were selected. The main experiment lasted for 7 weeks (7-56 days), using 288 chickens in a completely randomized design, with 3 replications, while, the environmental and genetic factors were controlled in an identical broiler housing.

The results showed that using water with different TDS contents had the most negative effects on mortality rate (%) in the rearing period and up to 56.2% mortality was recorded at the highest TDS content. Water consumption showed high and positive correlation (P < 0.05) with TDS (r = +0.74). Correlation between TDS and bedding moisture was also high (r = +0.65) and significant (P < 0.05). The differences between final body weight of control chickens and highest level of TDS were significant (P < 0.05). Feed intake also was affected by different TDS contents and showed similar results as with body weight. Increasing the TDS level decreased the abdominal fat in the female chickens and ash content of tibia in the male chickens. It is concluded that water TDS should be considered for the development of broiler chicken farms. Therefore, it is recommended that higher quality waters (with a TDS content of 3000 ppm) must be used for this purpose. Otherwise, appropriate systems should be used to improve physical and chemical composition of the water.

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This experiment was carried out to study the effect of ionophore drugs (Salinomycin, Lasalocid and their combination) on the performance of broiler chicks. Also their relationship with methionine (three levels) was evaluated. 1215 one-day-old commercial broiler chicks (Arian) were divided into 81 groups, 15 chicks per group, and tested in a completely randomized design with a 3×3×3 factorial experiment and three levels (0/0, recommended and 1.5 times recommended) of drugs and three levels (0.0, 1% and 0.2%) of supplemental methionine.

The results indicated that these drugs reduced body weight gain significantly (p<0.05) at 21 and 56 days of the experiment. Decreasing feed consumption and increasing feed conversion was significant (p<0.05) due to Lasalocid supplementation. Increasing drug level significantly (p<0.05) reduced body weight gain and feed intake and feed conversion was increased at 21 to 42 and 0 to 56 days of the experiment. The effect of supplemental methionine on body weight of 42 days (P<0.05) and feed conversion at 21 to 42 and 0 to 56 days (p<0.01) were significant. The interactions between drug type and drug level on body weight gain, feed consumption and feed conversion were significant (p<0.05). Lasalocid significantly (p<0.05) increased water intake. Drugs did not affect litter moisture and mortality. The results showed that Salinomycin was better than Lasalocid. Also supplemental methionine was not effective in compensating for the growth depression caused by ionophore drugs.

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This experiment was conducted to determine the requirements of vitamin supplement and available phosphorus in broiler chickens from 42 to 56 days of age. In a completely randomized design, with a 3×3×3 factorial arrangement, 270 one-day-old commercial broiler chicks were divided into 27 groups (replicates) with 9 treatments, 3 replicates and 10 chicks in each group. Each of the nine diets was given to each treatment from 42 days of age. Levels of vitamin supplement were 0.5, 0.25, 0% and available phosphorus levels were 0.27, 0.22, 0.16%. Diets were isocaloric and isoprotein. Group weight and feed consumption of each replicate were determined after 42 and 56 days of age and daily gain, daily feed consumption and feed conversion were calculated. Percent of carcass components and tibia ash were determined.

Results indicated that removal of vitamin supplement from 42 to 56 days of age did not have any significant effects on daily gain, daily feed consumption, feed conversion, live weight, viscera, abdominal fat, carcass weight, wings, neck and back bone. Also, reduction of available phosphorus did not have any significant effect on daily feed consumption, feed conversion, live weight, viscera, abdominal fat, carcass weight, breast meat, femurs, wings, neck and tibia ash. Interaction between vitamin and phosphorus were significant for daily gain, daily feed consumption, live weight, wings, neck and tibia ash (P<0.005) and were highly significant for breast meat, femurs, and back bone (P<0.00l).

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Two experiments were conducted to investigate the effect of dietary energy levels on the performance of Arian broiler chicks. Trial 1 was performed in summer and trial 2 in fall. Both experiments were accomplished in 5×2 factorial designs, involving 5 levels of dietary metabolizable energy and two sexes. Each of the 10 resulting treatments was replicated 4 and 3 times in trials 1 and 2, respectively. The metabolizable energy contents in diets number 1 to 5 were 2800, 2900, 3000, 3100 and 3200 Kcal/kg for starter (0-4 weeks) period and 2900, 3000, 3100, 3200 and 3300 Kcal/kg for grower (4-7 weeks) period, respectively. The ratios of energy to each nutrient were the same for all diets in each stage of the experiments.

In both experiments, body weight gain and feed conversion ratio improved significantly (P<0.01) when diets with higher levels of energy were consumed. Feed intake was affected (P<0.01) by the dietary energy content only in summer (trial 1) resulting from the reduced intake of chicks fed with the lowest energy level. Abdominal fat percentage was decreased (P<0.01) in chicks fed with the lowest energy diet in summer. In both experiments, the cost of the feed per unit of live body weight was reduced (P<0.01) in accordance with the reduction in diet density. As expected, body weight gain, feed conversion ratio, abdominal fat and cost of the feed per unit of live body weight for male chicks were significantly better than the same values for females (P<0.01).

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An experiment was carried out on 384 7d old commercial broiler chicks (Lohman) to study the effect of changes in source and level of dietary calcium and limestone particle size on the performance and tibial growth and calcification of broiler chicks. From day 1 to day 7, the chicks were fed with the commercial basal diet. On day 7, the chicks were weighted and randomly assigned to 64 groups, six chicks of similar body weight (82.2±5.4) per group. Each of the eight experimental diets was fed to eight groups of chicks for an experimental period of 49 days. Two calcium sources (oyster shell and limestone), two calcium levels (100% NRC and 85% NRC) and three particle sizes of limestone [ground (less than 0.15 mm), medium (0.6 to 1.18 mm) and coarse (1.18 to 4.75 mm)] were added to diets with the same energy based on a Randomized Complete Design, in which levels of calcium were nested into calcium sources. Particle sizes were nested into calcium sources and levels.

Limestone significantly increased phosphorus retention (in percentage of phosphorus ingestion) at the age of 21 and 56 days and increased tibial length, dry weight and ash weight at 56 days. Calcium level of 85% NRC significantly decreased feed intake and feed conversion, especially during the starter, and increased calcium retention (in percentage of calcium ingestion) at 21 and 42 days. Phosphorus retention and cortical thickness of tibia at 21 and 42 days, tibial dry weight, ash weight and ash percentage at 42 day, were significantly increased with calcium level of 100% NRC. Coarse and medium particle sizes of limestone as compared to ground particle size, significantly improved feed intake and feed conversion, especially during the starter. Medium particle size of limestone with calcium level of 85% NRC and coarse particle size of limestone with calcium level of 100% NRC, significantly improved tibia ossification characteristics and increased calcium and phosphorus retention. By using calcium level of 85% NRC, coarse and medium particle sizes of limestone compared to ground particle size, significantly diminished percentage of leg abnormalities.

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This experiment was carried out to study the effect of ionophore drugs (Salinomycin, Lasalocid and their combinations) on the performance of broiler chicks. Also their relationships with methionine (three levels) were evaluated. 1215 one-day-old commercial broiler chicks (Arian) were divided into 81 groups, 15 chicks per group, and tested in a completely randomized design with a 3×3×3 factorial experiment. Three drug types with three levels (0.0, the recommended level and 1.5 times the recommended level) of drugs and three levels (0.0, 0.1% and 0.2%) of supplemental methionine were used.

 The results indicated that the effect of sex on plasma cholesterol and triglyceride, percentage of bone ash and percentage of abdominal fat was significant (P<0.0l). Drug type had no effect on the characteristics under study. Drug level influenced percentage of bone ash, percentage of eviscerated carcass, and percentage of abdominal fat significantly (P<0.0l), (P<0.01) and (P<0.00l), respectively. Also methionine level influenced cholesterol and triglyceride (P<0.0l) significantly. Interaction effect of drug type and drug level on plasma cholesterol and triglyceride was significant (P<0.05). Interaction effect of drug and methionine level on cholesterol and triglyceride was significant (P<0.0l). The results showed that levels of this drug influenced carcass composition and also supplemental methionine had no influence on the modulating effect of these drugs on carcass composition.

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An experiment was conducted to determine growth and carcass characteristics of male broilers subjected to early feed restriction. Restricted birds were fed equivalent to 1/5*BW^0.67 Kcal/day/bird between days 7 and 14. On days 0 to 7 and 14 to 56, all chickens received feed ad-libitum. Diets of feed-restricted birds were supplemented with 15% higher methionin and cystine recommended by NRC (1994) during refeeding in starter and grower periods. No significant differences were observed for liver, breast, heart, carcass and liver fat between early restricted birds and ad-libitum control at 56 days of age. Body weight for restricted broilers were significantly (P<0.05) lower than that of controls in 56 days. However, restricted broilers had significantly lower total-feed to gain ratio than the unrestricted control. Restricted broilers that received diets high in total sulfur amino acids in starter and grower periods had singnificantly lower abdominal fat pad than control birds.

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Effect of supplemental phytase on phosphorus and protein utilization and performance of broiler chickens fed on eight different wheat varieties were evaluated. The phytate contents of wheat varieties were determined. In a completely randomized design with a 8*3 factorial arrangement, 384 day-old commercial male brioler chicks (HubbardPeterson) were divided into 96 groups, four chicks per group. Each of the 24 experimental diets (eight varieties) and three levels of phytase (zero, 500 and 1000 FTU/Kg) were given to four replicates for a period of 21 days. At 21 days of age, chickens of each replicate were weighed and killed by cervical dislocation. Ileal contents were collected and analyzed for P, N, phytate and chromic oxide. Left tibia of two birds in each replicate were removed, pooled and stored at -20^oC for bone ash determination. There was a significant (P<0.03) difference in phytate contents between different wheat varieties. Effect of wheat varieties on body weight, feed conversion ratio and bone ash was significant (P<0.05). Added phytase improved body weight, feed consumption, feed conversion ratio and bone ash significantly (P<0.05). Phytase added at 500 FTU/Kg, improved protein digestibility significantly (P<0.01), but increasing the supplement to 1000 FTU/Kg had no further effect. Difference between enzyme levels (500 and 1000 FTU/Kg) was not significant regarding body weight, feed consumption, feed conversion ratio and bone ash. Overall addition of phytase to the diets containing wheat caused an improvement in performance, protein digestibility, and phytase phosphorus utilization in broiler chickens, and can, therefore, be used in diets to reduce feed cost and environmental problems.

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In a completely randomized design (CRD) experiment with 6 treatments and 4 replicates per treatment, the effect of energy and protein dilution during 6-12 days of age was tested in broilers. Rice hull was used for dilution of energy and protein at levels of 0.05 (control), 10, 15, 20, 25 and 30 percent. The metabolizable energy and crude protein content of the experimental diets were 3089, 2780, 2626, 2472, 2317 and 2163 KCal/kg and 21.45, 19.29, 18.23, 17.16, 16.10 and 15.02 percent, respectively. The results indicated that diet dilution at early age (6-12 days) increased feed consumption but energy and protein intake and weight gain were reduced. No significant differences in body weight were observed due to compensatory growth among treatments. After feed restriction, feed intake was lower for the birds receiving diluted diets as compared to control. Meanwhile feed efficiency somewhat improved among the birds fed with diluted diets, but the differences were not significant. Diet dilution had no significant effect on carcass and abdominal fat percentage at the slaughter age (45 days). Diet dilution with rice hull at 20 and 25 percent decreased feed consumption and improved feed efficiency and, therefore, its use can reduce feed cost.

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This experiment was conducted to investigate the effects of intensity of restricted early feed and increased nutrient density after restriction period on performance and compensatory growth in broilers. Two hundred and eighty-eight broiler (Lohman) chicks in a completely randomized design in a 2*3 factorial arrangement of treatments were employed. Birds were fully fed from 7 to 13d or 100% of adlibitum intake on a daily basis. The diets were diluted at 25% and 50% levels with rice hulls. After the restriction period, birds were fed with a diet, formulated to meet all their nutrient needs, according to the NRC (1994) or 10% of protein, methionine and lysine above NRC in the realimentation diet from 13 to 21d. Body weight, feed intake, daily gain and feed conversion were determined weekly and selected carcass characteristics (liver, intestine and abdominal fat pad) were measured at 49 days of age. Feed restriction significantly (P<0.01) decreased body weight gain and feed conversion during the restriction period. Birds were able to fully recover body weight depression up to 49d. The intensity of restriction had no effect on body weight, feed intake, daily gain and feed efficiency at 49d (p>0.05). Increased nutrient density had no effect on growth rate, feed intake and feed efficiency for fully-fed birds and restricted birds at 49d. The results from this experiment showed that broiler chicks may be expected to gain weight similar to chicks with fully feeding even after restricted early feed if fed with NRC diets. The effect may be due to compensatory growth.

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In order to study the nutritive value of grades 1 and 2 wheat feed screening and macaroni wastes as energy resources, 360 21-day-old broiler chicks were divided into 36 groups of 10. In this experiment, each experimental levels of feedstuff was used at 0 (control group), 15, 30 and 45%. In addition, their apparent metabolizable energy (AMEn) was determined by Sibbald’s method. Daily feed intake of chicks fed by diets containing macaroni wastes and grade 1 wheat feed screening for 21 to 56 days of age was significantly lower than that in the control group (P<0.05). In contrast, body weight, daily weight gain and feed conversion had no significant differences during this period. However, in the total experimental period, the best feed conversion belonged to chicks fed with various levels of macaroni wastes and grade 1 wheat feed screening. Apparent metabolizable energy (AMEn) of macaroni wastes and wheat feed screening were 3700, 3270, and 2870 kcal/kg, respectively. According to the results of this experiment, it is possible to use macaroni wastes and grade 1 wheat feed screening at 45% and 30% levels in the diet of broiler chicks, respectively, without any undesirable effects on their performance.

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This experiment was conducted to study the effects of using cotton-seed meal on the performance and carcass yield of broiler chickens at different ages. The experiment was performed in a completely randomized design with four treatments and five replicates for each treatment. The experimental treatments included the levels of 0, 3.5, 7, and 10.5% of cotton-seed meal in diets fed to chickens at 7-21 days of age. Except for the control group, these levels for grower (21-42 d of age) was increased to 7, 14, and 21% and for finisher (42-56 d of age) to 14, 21, and 21%, respectively. For the purposes of this study, 260 day-old chicks were reared in litter until 7 days of age. On day 7, chicks were divided into 20 pens with 13 chicks in each pen. NRC (1994) recommendation was used in balancing experimental diets. The chickens were weighed weekly throughout the experimental period (7-56 d). The main observations were body gain, feed intake and feed conversion ratio. Physical analysis of carcass was done at the end of the experimental period and percentages of carcass, abdominal fat, liver, pancreas and digestive tract to live body weight were calculated. The use of cotton-seed meal and the increase of the levels through different ages had no significant effects on body weight, daily gain, feed intake, feed conversion ratio, and carcass components. Increasing the level of cotton-seed meal in the diet at 7-21 days of age had significant effects on feed intake (P<0.05) and increased it. The results of this experiment indicate that we can use cotton-seed meal at levels of 7,14, and 21% of diets, respectively, in starter, grower and finisher stages without having any adverse effects on the performance and carcass yield of broiler chickens.

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An experiment with a 33 factorial arrangement in a completely randomized design with 450 day-old broilers was conducted to study the effect of energy level and time of change from starter to finisher diets on performance and economic aspects of broilers. Broiler chickens were fed at three levels of dietary energy (2800, 3000, and 3200 KcalME/Kg) from 1-42 days of age. Starter and finisher diets were changed at 16, 21, and 26 days of age and then finisher diets were fed up to 42 days of age. The effect of diet energy and changing time from starter to finisher diets on body weight and feed conversion at 26 days of age were significant (P<0.01). By increasing energy level and changing time from starter to finisher diets, at this age, body weight increased and feed conversion ratio decreased. Energy conversion decreased by decreasing the levels of energy content of diet and increasing time of change from starter to finisher diets (P<0.01). At 42 days of age, the effects of diet energy and changing time from starter to finisher diets did not show any significant effects on feed and energy conversion in contrast, body weight at this age increased significantly as a result of increasing time of change from starter to finisher diets (P<0.05). From 1-42 days of age, the interaction between diet energy and changing time from starter to finisher diets on feed and energy conversion was significant (P<0.05). The results from this study suggest that increasing diet energy and changing time from starter to finisher diets for producing broilers with less than 2 kg will improve their general performance.

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To evaluate the effect of broiler growth rate and feed intake on development of the inflammatory response‚ commercial broiler diets were fed to 275 day–old chicks of the modern 2000 strain and 1957 random-bred strain. Half of the chicks had free access to feed while others were restricted. Twelve birds from each strain and group pens were removed‚ weighed, and housed in individual cages by their original feeding programs on 0‚ 7‚ 14, and 28 days. Three feed-restricted and three ad libitum birds from each strain were injected with 1-3 ml of 100 μg/ml solution of Salmonella typhimurium lipopolysaccharide on days 6‚ 13‚ 27‚ and 41, and 3 birds of each group were not injected‚ serving as controls. All birds were weighed and the liver‚ breast muscle‚ thymus gastro intestinal tract and bursa were removed on the day after injection. The thymocytes of the control birds were subjected to an interleukin–1 responsiveness assay. The 1957 strain birds were more severely affected by an inflammatory challenge going almost completely off feed‚ but the 2000 strain birds experienced a more drastic decline in growth rate after injection. Thymocytes of ad libitum birds were more sensitive to IL-1 than the restricted birds in week 4 (P=0.056). Interleukin-1 stimulated thymocytes of 2000 birds more effectively than the 1957 strain ones. In conclusion‚ the broiler inflammatory response was affected by growth rate and feed intake.