Effect of dietary protein content on live and carcase performance of heterozygous naked neck and normally feathered broilers

1. An experiment was conducted to determine the effect of different dietary protein contents on the performance of naked neck (Na/na) and normally feathered (na/na) broilers.

2. Chicks from the two genotypes were reared in wire‐floored cages and divided at random into 3 groups. Birds were fed on high protein (HP, 12.99 MJ ME, 238 g crude protein/kg and 12.94 MJ ME, 216 g crude protein/kg from 0 to 3 and 3 to 7 weeks, respectively), medium protein (MP, 12.99 MJ ME, 219 g crude protein/kg and 12.87 MJ ME, 201 g crude protein/kg from 0 to 3 and 3 to 7 weeks), and low protein (LP, 12.94 MJ ME, 205 g crude protein/kg and 12.75 MJ ME, 184 g protein/kg from 0 to 3 and 3 to 7 weeks) diets.

3. The LP diets resulted in a significantly lower daily body weight gain of males from 0 to 3 weeks. Dietary protein content had no effect on body weight gain from 3 to 7 weeks, body weight at 7 weeks, and the food intake of birds. Carcase composition of birds from both genotypes was unaffected by dietary protein.

4. Naked neck birds had significandy higher body weights at 7 weeks. Yields of carcase and breast of Na/na males were significantly higher than those of na/na males. There were no significant differences between females from the two genotypes as regards carcase yield.

5. It was concluded that the dietary protein requirements of naked neck birds were similar to those for normally feathered birds.     

Influence of dietary energy on bird performance,carcase parts yields and nutrient composition of breast meat of heterozygous naked neck broilers reared at natural optimum and summer temperatures

1. Heterozygous naked neck birds were raised under natural spring (average 21.2°C) and summer temperatures (average 27.1°C) to investigate the influence of dietary energy on broiler performance, carcase yield and nutrient composition of breast meat. 2. Birds were fed on a low energy diet of 12.12 MJ ME/kg, a medium energy diet of 12.96 MJ ME/kg and a high energy diet of 13.79 MJ ME/kg with 2 protein concentrations per energy treatment, 230 and 200 g/kg, from 0 to 3 and 3 to 7 weeks of age, respectively. 3. Summer rearing resulted in a decrease in body weight, body weight gain, carcase weight and carcase part yields of birds. 4. Increasing dietary energy from 12.12 to 13.79 MJ ME/kg increased body weight at 3 and 7 weeks, body weight gains from 0 to 3 and 3 to 7 weeks, carcase weights and relative abdominal fat weights of birds in a linear manner. There was no effect of dietary energy on the nutrient composition of breast meat. 5. It was concluded that there was no differences in dietary energy requirements of heterozygous naked neck birds when grown under natural optimum (21.2°C) and summer temperatures (27.1°C).     

Effect of season and dietary energy concentration on composition and strength of skin in naked neck fowl

1. Two experiments, in spring and summer, were conducted to evaluate the effect of dietary energy concentration on the composition and strength of the skin of naked neck fowl. The heterozygous naked neck birds were also compared with their normally feathered sibs under summer temperatures. 2. The average temperatures were 21.2°C and 27.1°C in spring and summer experiments, respectively. Three concentrations of dietary energy were fed to the birds. The diets used were: a low energy diet of 12.12 MJ ME/kg; a medium energy diet of 12.96 MJ ME/kg; and a high energy diet of 13.79 MJ ME/kg. Two protein concentration per energy treatment, 230 and 200 g/kg, respectively were used from 0 to 3 and 3 to 7 weeks of age. 3. A significant season sex interaction showed that the skin of males had higher protein and collagen and lower dry matter and fat content than that of females, when grown under summer conditions. No sex differences were present under spring conditions. 4. The differences between sexes was not significant in spring but males had stronger skin than females in summer. Neither ambient temperature nor dietary energy concentration significantly affected skin displacement of naked neck birds. 5. In comparing the naked neck and their normally feathered sibs in the summer experiment, it was found that naked neck birds had lower skin fat content and higher skin protein content than normally feathered birds.     

Effect of the naked neck gene on carcase composition and immunocompetence in chicken

1. An experiment was conducted to study the effect of naked neck gene (Na) on carcase measurements and some immunological responses of chickens. 2. The presence of naked neck gene in a single or double state increased body weight. 3. The naked neck genotypes (NaNa or Nana) exhibited higher relative weight of dressed carcase, drumstick and breast muscles compared to normally feathered individuals (nana). The proportion of abdominal fat was decreased in both naked neck genotypes compared with normally feathered ones. 4. A higher (non-specific) cell-mediated immune response was evoked in Na gene bearing birds. 5. Higher concentrations of antibodies occurred after injection of sheep red blood cells into naked neck birds, particularly at 14 d post-secondary injection. 6. The NaNa birds had a higher heterophil/lymphocyte ratio than Nana and nana siblings.     

Effects of divergent selection for incidence of tibial dyschondroplasia (TD) on purebred and crossbred performance. 2. Processing yield

1. An experiment was conducted to determine the effect of selection for high (H) or low (L) incidence of tibial dyschondroplasia for 7 generations on processing performance of broilers. 2. Birds were obtained from diallel matings of the H and L lines (HH, HL, LH, and LL) and a randombred control (CC) line. Birds were reared to 7 weeks of age under standard management conditions. All birds were processed at 7 weeks of age. Body weight at 7 weeks, carcase weight, and carcase part weights were recorded on each bird. 3. An interaction between sire line and dam line was caused by lighter body and carcase weight at 7 weeks of age in HH birds than from the birds of the other crosses. 4. Birds by L line dams had heavier drumstick weights. The influences of sire line and dam line on weight of total breast muscle were not significant. Thigh weights and Pectoralis minor weights were lighter in HH line birds than those other matings. 5. Heterosis for body weight and for weights of carcases, drumstick and thigh was negative. Total breast muscle weight and P. major weight did not show significant heterosis. 6. It was concluded that selecting against TD does not reduce processing yield of broilers.     

Thermoregulation in naked neck chickens subjected to different ambient temperatures

1. Heterozygous (Na/na) naked neck chickens and their normally feathered (na/na) sibs, were exposed to constant ambient temperatures (Ta) ranging between 15 and 35C and 12h: 12h diurnal high:low temperatures of 15C:35C. 2. No significant effect of genotype was obtained in weight gain and food intake. However, the naked neck birds tended to gain somewhat more weight at high Ta and consume more food at low Ta. 3. At 35C Na birds showed better regulation of body temperature (Tb) and demonstrated considerably higher radiation from the neck. 4. The greater food intake of the naked neck chickens at 15C was associated with significantly higher packed cell volume, haemoglobin concentration, heart and liver size. These appear to involve both higher heat production and haemodynamic changes to accommodate the higher oxygen demands of the naked neck chickens at low Ta. 5. The results indicate the ability of the naked neck chickens, on the one hand to thermoregulate at low Tas and, on the other their slightly better capacity to maintain Tb at high Tas. However, no genotype advantage was obtained under diurnal cyclic temperature conditions.     

High dietary niacinamide and performance of male poults at 16 weeks of age

1. Male poults were fed diets with 50 and 100 mg supplemental niacinamide/kg and grown at stocking densities of 3.2 and 4.3 birds/m2 from 56 to 112 d. 2. At 50 mg/kg niacinamide high stocking density (HSD) depressed 112 d body weight and gain from 56-112d. High dietary niacinamide (100 mg/kg alleviated the growth depression under HSD but decreased body weight gain under low stocking density (LSD). 3. Dressed yield and hock width were not affected by dietary niacinamide or stocking density. 4. Dressed carcase composition was altered by stocking density. The dressed carcase of HSD birds contained 3.7% more protein and 7% less fat. 5. High dietary niacinamide tended to increase carcase protein (+2.4%) and decrease carcase fat (-4.0%).     

Effects of dietary protein concentration and specific amino acids on body weight,body composition and feather growth in young turkeys

1. Two randomised block factorial experiments were conducted to investigate the relationships between the effects of dietary crude protein and specific amino acid concentrations on the relative growth of the body and feathers of young turkeys. 2. Decreasing dietary crude protein concentration from 300 to 180 g/kg in experiment 1 reduced the body and breast muscle weights of a large male line of turkeys proportionally by 0.44 and 0.52 compared with 0.19 and 0.24 in a small traditional line. 3. Decreasing dietary crude protein concentration was associated with a maximum reduction in feather weight of 0.18 and 0.24 respectively in male line and traditional turkeys. The length of the feathers in the cranial region of the breast decreased from 26 to 19mm in the traditional line compared with an increase from 14 to 25 mm in male line turkeys. 4. Decreasing dietary crude protein concentration was associated with an increase in the fat content of the feather-free carcase. Male line turkeys had a higher carcase fat and lower feather dry matter content than the traditional turkeys. 5. It was concluded that dietary crude protein was preferentially partitioned to feather rather than muscle growth in the male line in contrast to a traditional line of turkeys in which the growth of feathers and muscle were affected equally. 6. In experiment 2, the amino acids arginine, valine, methionine and tyrosine were added separately to a common basal ration (180g CP/kg) to raise their concentration to that of the control ration (260 g CP/kg). Each ration was fed ad libitum to male line turkeys from 2 to 6 weeks of age. 7. Amino acid supplementation increased body and breast muscle weights. 8. Compared with the basal ration, tyrosine was associated with a reduction in feather weight whereas valine had no effect. Supplementation with arginine and methionine resulted in increased feather weights that were similar to that of the controls. 9. It was concluded that arginine and methionine were used preferentially and are essential for feather growth. Excess amino acids that are not required for feather growth such as tyrosine and valine were used for increased body growth and resulted in relatively poor feather cover. 10. The results suggest that feather growth was maintained as much as possible at the expense of body growth when the amino acid concentration of the ration was less than that required to maximise body and muscle weight gain in large male line turkeys.     

Growth performance of crossbred naked neck and normal feathered laying hens kept in tropical villages

1. Two experiments were conducted to develop naked neck (Na/na) and normal feathered (na/na) crossbreds and compare their growth performance, linear body measurements and carcass characteristics in the first and second filial generations.

2. In the first experiment, 4 indigenous naked neck males (Na/na) were mated to 36 Lohmann commercial females (na/na) in a ratio of 1:9. The two genotypes (Na/na, na/na) were allocated randomly according to batches of hatch, sire lines and sex to three different villages.

3. In the second experiment, 10 males and 100 females of F₁ Na/na birds were selected and mated inter se in a ratio of 1:10. The three genotypes (Na/Na, Na/na and na/na) were compared in a randomised complete block design experiment, with the three villages, hatch and sex as blocks and the three genotypes as treatments. F₁ Na/na birds had significantly higher (P < 0.05) feed conversion ratio, body weight, body weight gain, linear body measurements, survivability and carcass yield than their na/na counterparts.

4. In the F₂ generation, Na/Na and Na/na birds had significantly higher (P < 0.05) feed conversion ratio, body weight, body weight gain, linear body measurements, survivability and carcass yield compared to their na/na counterparts.

5. The birds showing the naked neck phenotype appeared to show superior performance compared to normal feathered birds and could be exploited for potential utilisation in local poultry production.     

Chromium picolinate, rather than biotin, alleviates performance and metabolic parameters in heat-stressed quail

1. The effects of chromium picolinate and biotin supplementation alone and in combination on performance, carcase characteristics, malondialdehyde (MDA), vitamin C, vitamin E, glucose and cholesterol levels were evaluated in Japanese quail exposed to high ambient temperature. 2. Two hundred and forty quails (10d old) were assigned randomly to 4 dietary treatments at room temperature (22 degrees C; thermoneutral, TN) or ambient (34 degrees C for 8 h/d; heat stress, HS). Both TN and HS were fed either on a basal (control) diet or the basal diet supplemented with 400 microg of Cr/kg (Cr group), 0.5 mg of biotin/kg of diet (biotin group) or both (Cr + Biotin group). 3. Supplementing the diet of heat-stressed quails with chromium picolinate improved live weight gain, feed intake, feed efficiency and carcase traits. Biotin supplementation during TN and HS conditions did not have any beneficial effects on body weight gain, feed intake, feed efficiency or carcase traits. 4. Either in combination or alone, chromium picolinate increased serum concentrations of vitamins C and E, but decreased MDA, glucose and cholesterol concentrations in birds kept at high ambient temperature. There was no difference in vitamins C and E and MDA concentrations between birds given chromium picolinate and birds receiving chromium picolinate plus biotin, while glucose and cholesterol levels were significantly lower in all groups. The lowest concentrations of cholesterol and glucose were found in the combination group under both TN and HS conditions. An interaction between diet and temperature was detected for glucose and cholesterol concentrations. 5. Excretion rates for zinc, iron and chromium were lower in TN groups than in the corresponding HS groups. Supplementing diet with chromium picolinate and chromium picolinate plus biotin decreased excretion of minerals while biotin alone did not effect excretion of minerals. 6. Chromium supplementation, but not biotin supplementation, attenuated the decline in performance and antioxidant status resulting from heat stress.     

Lack of interrelationship between the effects of dietary factors and food withdrawal on carcase quality of broiler chickens

1. Four factorial experiments were carried out to determine whether there is any interrelationship between dietary energy-to-protein (E:P) ratio (experiments 1, 2 and 3) or pelleting the diet (experiment 4) and the duration of food withdrawal (FW), in their effect on carcase quality of broiler male chickens. The quality was evaluated by yields of carcase and breast meat, abdominal fat pad size, and the content and composition of the fat in the meat. The effect of sex on the response to FW was also determined in experiment 3 and that of age in experiment 4. 2. The diet with an E:P ratio higher than recommended decreased the weights of carcase and breast meat significantly (P 0.05) in 2 of the 3 experiments, and consistently increased the size of the abdominal fat pad and the fat content in thigh, but not in breast meat. Abdominal fat pad and the fat in meat of birds fed on this diet contained a significantly higher amount of oleic acid and a lower amount of linoleic acid, than the fat of birds fed on the diets with the recommended and the low E:P ratios. The pellets increased significantly the weights of carcase and breast meat and the relative size of abdominal fat pad. 3. FW for 24 h decreased significantly the weight at slaughter in all 4 experiments, carcase weight in 3 experiments, and breast weight in 1 experiment. However, it did not affect the relative size of the abdominal fat pad, the fat content in thigh and breast meat, and the composition of fatty acids in these tissues and in abdominal fat. None of the variables mentioned was affected significantly by the interaction between the dietary factors evaluated, sex or age of the birds on the one hand, and FW on the other hand. 4. It is concluded that the effect of 24 h of FW on weight at slaughter, carcase and breast meat weights and on fattening, is not affected by dietary E:P ratio, pelleting the diet, or sex and age of the broilers.     

Effect of dietary concentrations of fat and energy on fat deposition in broilers divergently selected for high or low abdominal adipose tissue

1. Fat deposition in abdominal, mesenterial, sartorial and gizzard adipose tissues (AT), liver, breast muscle, skin and carcase was studied in male broilers, selected for high (HF) and low (LF) abdominal fat and fed on diets differing in energy density and total fat content. 2. There were no significant differences in body weight in the experimental groups. The relative weight (g/kg body weight) of the dissected adipose tissues was higher in HF than in LF birds. Fat concentration in the AT (sartorial excepted), skin and body was higher in the HF compared with the LF birds. The lines did not differ significantly in liver and breast muscle fat content. 3. Abdominal AT was affected by selection or dietary fat more than other AT and total body fat. 4. In the HF birds increasing energy density from 12.3 to 13.4 MJ/kg (dietary fat kept constant: 5.46 g/MJ) significantly increased the weight of the abdominal, mesenterial and sartorial AT. Increasing dietary fat (at both energy densities) decreased the weight of the AT, whereas increasing both energy and fat did not affect it. In the LF birds, similar but milder and insignificant trends were observed. It is suggested that this interaction has biological significance.     

Effects of dietary protein and energy concentrations on performance and carcase characteristics of chukar partridge (Alectoris chukar) raised in captivity

1. This study was conducted to determine the effects of starter and grower diets with differing crude protein (CP) and metabolisable energy (ME) concentrations on the body weight (BW), live weight gain (LWG), feed consumption (FC), feed conversion ratio (FCR), and carcase, breast+back, rump, wing, neck and abdominal fat weights of chukar partridge raised in captivity. 2. Chukar partridges were fed on starter diets containing 4 concentrations of CP (160, 200, 240, 280 g/kg) and 4 concentrations of ME (10.9, 11.7, 12.6, 13.4 MJ/kg) from hatch to 8 weeks of age; they were fed on grower diets containing 4 concentrations of CP (150, 175, 200, 225 g/kg) and 4 concentrations of ME (11.9, 12.6, 13.2, 13.8 MJ/kg) from 9 to 16 weeks of age. All diets contained at least 5.5 g/kg methionine, 15 g/kg lysine and 10 g/kg methionine+cystine. Sixteen starter and 16 grower diets were arranged in a 4 x 4 factorial design with 4 levels of CP and 4 levels of ME. Each treatment was replicated three times with each replicate consisting of 5 males and 5 females. 3. Partridges fed on a starter diet containing 160 g CP/kg were significantly lighter at 8 weeks of age than those in groups given diets containing a higher CP. However, at 16 weeks of age, the differences in BW among treatments had disappeared. Throughout, there were no significant effects of ME concentration on BW and LWG. 4. The daily mean FC for the 0 to 8 week and 0 to 16 week periods was not affected by dietary CP concentration. For the 9 to 16 week period, the partridges fed on a grower diet containing 225 g CP/kg consumed more feed than those given a diet containing 175 g CP/kg. 5. The highest FCR for the 0 to 8 week period was in partridges fed on a starter diet containing 160 g CP/kg. For the 9 to 16 week period, the lowest FCR was in partridges fed on a grower diet containing 150 g CP/kg. For the 0 to 16 week period, there was not a significant effect of dietary CP concentration on FCR. The daily mean FC and the FCR for the 0 to 8, 9 to 16 and 0 to 16 week periods decreased when the ME concentration of the starter and grower diets increased. 6. The carcase, rump and breast+back weights of the male partridges increased when the ME content of the diets increased. Weights of all carcase components of the male partridges were significantly greater than those of the carcase components of the females. 7. There were no significant interactions between CP and ME concentrations on BW, LWG, FC, FCR and carcase characteristics. 8. We conclude that the starter diet for chukar partridges raised for meat production should contain at least 200 g CP/kg, 11.7 MJ ME/kg, and the grower diet should contain 150 g CP/kg, 12.6 MJ ME/kg.     

Influence of activity and dietary energy on broiler performance,carcase yield and sensory quality

1. A total of 2560 male and female Ross broilers were raised to 42 days of age in a 2 × 2 treatment factorial arrangement experiment to investigate the influence of different degrees of physical activity and dietary energy on broiler performance, abdominal fat content, carcase yield and sensory quality.

2. Vertical fans were used to force the treatment birds to walk 3 to 4 times as far as the normal activity birds; birds were fed a normal and a high energy diet (12.55 compared with 13.81 MJ ME/kg) with the same energy/protein, energy/lysine and energy/methionine + cystine ratios.

3. High activity birds had greater body weight ( + 4.1%), food intake ( + 5.1%) and ME intake ( + 5.1%) than normal activity birds. Birds receiving high energy diet had a lower food conversion and food intake than birds receiving normal energy diet. There were no significant differences in body weight or ME intake between birds with different diets.

4. Slaughter yields, both absolute and relative to live body weight, were affected by activity or dietary energy to varying degrees. Breast meat was increased with more activity. The absolute weight of abdominal fat was independent of activity and in males the relative weight of abdominal fat was decreased in high activity birds.

5. Different degrees of activity and dietary energy had only minor influences on broilers' sensory quality.     

Can betaine partially replace or enhance the effect of methionine by improving broiler growth and carcase characteristics?

1. Growth rates and carcase characteristics were measured in male broiler chickens fed on a control diet deficient in methionine (c. 2·8 g/kg methionine) or a series of diets containing graded levels of betaine or DL-methionine or both additives. 2. We aimed to answer 2 main questions. First, can betaine replace part of the methionine in a broiler ration? Secondly, is there a synergism between methionine and betaine? 3. Birds given the control diet or that supplemented only with betaine ate less, grew more slowly, had higher food convension ratio (FCR) and varied more in mass at 42 d than birds fed diets with DL-methionine. Adding 1·2 g/kg DL-methionine to the control ration produced the heaviest birds at 42 d (2500 g) with the 2nd heaviest breast muscle (366 g). 4. After correcting for treatment differences in body mass (analysis of convariance), birds fed on the control diet and the diet supplemented with betaine only, had relatively lighter breast muscles but relatively heavier abdominal fat pads than those of birds given diets supplemented with DL-methionine. However, adding betaine to diets containing added methionine further improved the relative breast muscle yield. 5. After correcting for differences in body mass between treatments, birds fed on diets containing most methionine had lighter viscera than birds fed diets deficient in methionine. This demonstrated gut plasticity, suggesting that the viscera enlarged to sequester methionine from low-methionine diets. 6. Our data refute the hypothesis that betaine can substitute for methionine in broilers fed diets that are marginally deficient in methionine plus cystine. However, betaine may improve carcase composition, especially breast meat yield.     

Response of growing goslings to dietary methionine from 28 to 70 days of age

1.?A dose–response experiment with 5 dietary methionine concentrations (2?3, 3?3, 4?3, 5?3 and 6?3 g/kg) was conducted with goslings to estimate the growth performance and carcase quality response of growing goslings to dietary methionine from 28 to 70 d of age.

2.?A total of 150, 28-d-old birds were randomly distributed to 15 pens with 10 birds per pen according to similar pen weight. There were 5 dietary treatments, each containing three replicate pens. Weight gain, feed intake and feed/gain of goslings from each pen were measured at 2-week intervals from 28 to 70 d of age. At 70 d of age, 4 goslings were selected randomly from each pen and slaughtered to evaluate carcase quality.

3.?Significant effects of dietary methionine on daily weight gain (28–56 d) and daily feed intake were determined. Daily weight gain from 28 to 42 d and 28 to 56 d, daily feed intake and gain/feed showed significant quadratic response to increasing dietary methionine, while abdominal fat proportion showed a significant linear response.

4.?When dietary CP concentration was 158?2 g/kg, the optimal methionine concentrations for growing goslings from 28 to 42 d and 28 to 56 d of age for maximum daily weight gain were 4?07 and 4.14 g/kg, respectively.     

Effect of low protein diets for growing Leghorn pullets upon subsequent laying performance

An experiment was conducted with White Leghorn pullets to study the effect on laying performance of dietary protein content and amino acid supplementation during the growing period. From 0 to 6 weeks of age birds fed on diets containing either 149 g protein/kg supplemented with methionine and lysine or 182 g protein/kg grew faster than those fed on a diet containing 149 g protein/kg alone. However, only those fed on the supplemented diet utilised their food more efficiently. From 7 to 20 weeks of age neither body weight gain nor food utilisation was affected by the dietary protein content. Pullets fed the low protein diet supplemented with 2 g methionine/kg and 2.5 g lysine/kg during the period of 0 to 6 weeks of age had significantly better egg production than birds fed the low protein diet alone. The dietary protein content during 7 to 20 weeks of age did not influence subsequent egg production.     

Dietary L-arginine supplementation beneficially regulates body fat deposition of meat-type ducks

1. Unlike mammals, uricotelic species, such as the duck, cannot synthesise endogenous arginine (Arg). This study was conducted to test the hypothesis that dietary L-Arg supplementation might regulate body fat deposition in ducks without affecting their fast growth rate. 2. A total of 160 21-d-old male and female White Pekin ducks were assigned randomly to two treatments: a non-supplemented control and supplementation at 10 g/kg L-Arg of a maize and soybean meal-based diet. 3. The 3-week feeding trial showed that the addition of L-Arg had no significant effect on feed intake, but significantly increased body weight gain by 5·2 %, breast muscle weight relative to live body weight by 9·9%, carcase crude protein content by 9·2%, ether extract content in breast muscle by 11·9%. Arg supplementation significantly decreased skin with fat and abdominal fat pad contents by 7·6% and 4·9% respectively and the ether extract content of carcase by 7·2%. 4. The results of this study indicate that a diet with 10 g/kg supplemental L-Arg could reduce the fat deposition of carcase and abdominal adipose cell size (diameter and volume), enhance intramuscular fat in breast muscles, as well as increase muscle and protein gain. The decreased fat depot in the carcase may be attributed to a reduction of hepatic lipogenic enzyme activity.     

Effect of different non-chloride sodium sources on the performance of heat-stressed broiler chickens

1. One hundred and eighty 1-d-old broiler chicks were used to evaluate the effect upon broiler performance during severely hot summer months of three different sodium salts: sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3) and sodium sulphate (Na2SO4), in starter and finisher diets having an identical electrolyte balance (DEB) of 250 mEq/kg. 2. The non-chloride sodium salts were added to contribute the same amount of sodium and were substituted at the expense of builder's sand in the basal diets containing common salt (NaCl) as Na and Cl source. 3. Each diet was fed to three experimental units having 15 chicks each until 42 d of age. Severe heat-stress conditions, maintained in the rearing room, were indicated by high average weekly room temperature (minimum 29.3 degrees C; maximum 38.0 degrees C). 4. Diets containing sodium salts gave better body weight gain, feed intake and feed to gain ratio than the control diet. Sodium salts also enhanced water intake as well as water to feed intake ratio. This effect was more pronounced in broilers fed NaHCO3 supplement (with NaCl in the basal diets). 5. The increased water intake resulted in lower body temperature in heat-stressed birds fed NaHCO3 supplemented diet than in birds fed other sodium salts. A lower mortality rate was noted with NaHCO3 (15.15%), Na2CO3 (13.64%) and Na2SO4 (15.15%) supplements than with the control (33.33%) treatment. 6. Better carcase and parts yield were observed in sodium supplemented broilers. Sodium salts reduced the alkalotic pH and enhanced the blood sodium content, which ultimately improved the blood electrolyte balance and overall performance of heat-stressed broilers. 7. Supplementing broiler diets with sodium salts improved the live performance of heat-stressed broilers and better productive performance was noted with NaHCO3 than other sodium supplements.     

Effects of chromium nicotinate on performance, carcase characteristics and blood chemistry of growing turkeys

1. The objective of this trial was to study the effects of chromium nicotinate (Cr) supplementation on the performance, carcase characteristics and blood constituents of 9 to 22 week-old male turkeys. 2. Fifty-four 8-week-old male turkeys weighing 2.9 +/- 0.28 kg were allocated at random into 9 groups with 3 dietary treatments and 3 replicates. The dietary treatment was different dietary concentrations of chromium in the basal diet, to provide 0 (control), 1 or 3 mg/kg. The feeding trial lasted for 14 weeks. 3. Results showed that 1 mg/kg chromium supplementation significantly improved weight gain and food intake at 9 to 18 weeks of age but did not significantly influence performance at 19 to 22 week of age. The breast and thigh muscle were significantly increased in birds receiving 1 mg/kg chromium supplementation but were decreased by 3 mg/kg of supplementation. 4. Dietary chromium supplementation did not significantly influence other serum constituents, including insulin, HDL, VLDL+LDL, HDL-C, VLDL-C+LDL-C, total protein, albumin, and gamma-globulin at 18 and 22 weeks of age. 5. The serum triacylglycerol (TG) and uric acid contents were significantly increased, while glycerol and alpha-globulin were significantly reduced by 3 mg/kg chromium supplementation. However, 1 mg/kg chromium supplementation significantly reduced serum cholesterol and glycerol at 18-weeks old. At 22 weeks of age, 1 mg/kg chromium supplementation significantly increased serum glucose and decreased the uric acid concentration whereas 3 mg/kg chromium supplementation significantly increased the creatinine concentration and decreased beta-globulin concentration.