Egg Storage Time Affects Incubation Yield and Hatch Window in Pekin Ducks (Anas Boschas)

The objective of this study was to evaluate the effect of storage time on albumen quality, incubation yield, and hatch window in Pekin ducks (Anas boschas). A total of 1302 eggs were randomly distributed to seven treatments according to the storage time with durations ranging from 1 to 14 days. Each treatment consisted of 186 eggs with a two-day storage interval between treatments. The pH and Haugh unit (HU) of the albumen, egg weight loss during incubation (WL), hatchability (HTCH), incubation duration (ID), hatch window, asymmetry (ASS), percentile kurtosis (PK), and embryonic mortality were analyzed. A linear effect was observed forthe WL, ID, and PK and a quadratic effect forpH, HU, and HTCH over time. No significant effect of storage time was observed on ASS. Post-pipping embryonic mortality was linearly affected by storage time. Prolonging the storage period above 10 days reduces albumen quality and hatchability, delays the hatch of Pekins, and results in a higher percentage of post-pipping mortality.(AU)

Egg Storage Time Affects Incubation Yield and Hatch Window in Pekin Ducks (Anas Boschas)

The objective of this study was to evaluate the effect of storage time on albumen quality, incubation yield, and hatch window in Pekin ducks (Anas boschas). A total of 1302 eggs were randomly distributed to seven treatments according to the storage time with durations ranging from 1 to 14 days. Each treatment consisted of 186 eggs with a two-day storage interval between treatments. The pH and Haugh unit (HU) of the albumen, egg weight loss during incubation (WL), hatchability (HTCH), incubation duration (ID), hatch window, asymmetry (ASS), percentile kurtosis (PK), and embryonic mortality were analyzed. A linear effect was observed forthe WL, ID, and PK and a quadratic effect forpH, HU, and HTCH over time. No significant effect of storage time was observed on ASS. Post-pipping embryonic mortality was linearly affected by storage time. Prolonging the storage period above 10 days reduces albumen quality and hatchability, delays the hatch of Pekins, and results in a higher percentage of post-pipping mortality.

Effect of Broiler Breeder Age and Glutamine Supplementation on the Development of the Intestinal Mucosa of 7-Day-Old Chicks

The aim of this study was to evaluate the possible effects of glutamine and broiler breeder age on the development of intestinal mucosa in broiler chicks during first week of age. For this purpose, 32 one-day-old broiler chicks were distributed according to a completely randomized experimental design in a 2 x 2 factorial arrangement. Treatments consisted of two broiler breeder ages (30 and 60 weeks) and two dietary glutamine supplementation levels (0% and 1%). The morphological development of intestinal mucosa, particularly villus height and crypt depth, was evaluated. The results showed that the supplementation with 1% of glutamine influenced the development of villus height in the duodenum (p=0.009), jejunum (p = 0.006), and ileum (p = 0.001), as well as crypt depth in the jejunum (p = 0.037) of 7-day-old broilers. These results suggest that the presence of glutamine influenced the development of intestinal mucosa during the first week of age, when these tissues are highly influenced by dietary components, especially by trophic agents. The results show that broiler breeder age (30 or 60 weeks) did not influence the evaluated parameters.

Effect of Broiler Breeder Age and Glutamine Supplementation on the Development of the Intestinal Mucosa of 7-Day-Old Chicks

The aim of this study was to evaluate the possible effects of glutamine and broiler breeder age on the development of intestinal mucosa in broiler chicks during first week of age. For this purpose, 32 one-day-old broiler chicks were distributed according to a completely randomized experimental design in a 2 x 2 factorial arrangement. Treatments consisted of two broiler breeder ages (30 and 60 weeks) and two dietary glutamine supplementation levels (0% and 1%). The morphological development of intestinal mucosa, particularly villus height and crypt depth, was evaluated. The results showed that the supplementation with 1% of glutamine influenced the development of villus height in the duodenum (p=0.009), jejunum (p = 0.006), and ileum (p = 0.001), as well as crypt depth in the jejunum (p = 0.037) of 7-day-old broilers. These results suggest that the presence of glutamine influenced the development of intestinal mucosa during the first week of age, when these tissues are highly influenced by dietary components, especially by trophic agents. The results show that broiler breeder age (30 or 60 weeks) did not influence the evaluated parameters.(AU)

Evaluation of Free-Range broilers using the welfare quality® protocol

Scientific information on the welfare of broilers reared in alternative systems is scarce. The objective of this study was to assess the welfare of free-range broilers using the Welfare Quality® protocol. Free-range broilers reared in ten farms were observed, and measures were made in broilers of five of these farms. The collected data were transformed into scores (0-100), with higher scores indicating better welfare, except for emotional states. Prevalence percentages were calculated for the remaining data. Median (min-max) scores were 81 (63-98) for lameness, 93 (83-99) for hock burn on the farm, 100 (95-100) for plumage cleanliness, 35 (8-70) for podermatitis on the farm, 56 (26-88) for density, 53 (20-53) for dust, 34 (14-67) for litter quality, 93 (41-100) for drinkers, and 100 (100-100) for birds panting or huddling on the farm. The following average (min-max) prevalence percentages were obtained: total mortality 2.0% (1.4-7.2%), culling 0.0% (0.0-2.2%), feed withdrawal time 875 min (715-945 min), water withdrawal time 220 min (170-275 min), dead on arrival at the processing plant 0.00% (0.00-0.01%), broken wings 0%, (0-0%), inefficient stunning 3.9% (1.3-6.7%), pre-stun shock 49.3% (26.7-56.8%), hepatitis 4.5% (1.8-11.0%), bruising 9.3% (6.7-16.7%), and ascites 0% (0-0%). The negative broiler welfare points detected were pododermatitis, litter quality, density, dust, culling, feed withdrawal time, inefficient stunning, pre-stun shock, and hepatitis. The positive points identified were the absence of birds panting or huddling on the farm; low prevalence of lameness, hock lesions, dead on arrival, broken wings, and ascites; good plumage cleanliness scores, and short water withdrawal time.

Evaluation of Free-Range broilers using the welfare quality® protocol

Scientific information on the welfare of broilers reared in alternative systems is scarce. The objective of this study was to assess the welfare of free-range broilers using the Welfare Quality® protocol. Free-range broilers reared in ten farms were observed, and measures were made in broilers of five of these farms. The collected data were transformed into scores (0-100), with higher scores indicating better welfare, except for emotional states. Prevalence percentages were calculated for the remaining data. Median (min-max) scores were 81 (63-98) for lameness, 93 (83-99) for hock burn on the farm, 100 (95-100) for plumage cleanliness, 35 (8-70) for podermatitis on the farm, 56 (26-88) for density, 53 (20-53) for dust, 34 (14-67) for litter quality, 93 (41-100) for drinkers, and 100 (100-100) for birds panting or huddling on the farm. The following average (min-max) prevalence percentages were obtained: total mortality 2.0% (1.4-7.2%), culling 0.0% (0.0-2.2%), feed withdrawal time 875 min (715-945 min), water withdrawal time 220 min (170-275 min), dead on arrival at the processing plant 0.00% (0.00-0.01%), broken wings 0%, (0-0%), inefficient stunning 3.9% (1.3-6.7%), pre-stun shock 49.3% (26.7-56.8%), hepatitis 4.5% (1.8-11.0%), bruising 9.3% (6.7-16.7%), and ascites 0% (0-0%). The negative broiler welfare points detected were pododermatitis, litter quality, density, dust, culling, feed withdrawal time, inefficient stunning, pre-stun shock, and hepatitis. The positive points identified were the absence of birds panting or huddling on the farm; low prevalence of lameness, hock lesions, dead on arrival, broken wings, and ascites; good plumage cleanliness scores, and short water withdrawal time.

Impact of particle size, thermal processing, fat inclusion, and moisture addition on starch gelatinization of broiler feeds

The present study evaluated the effect of feed particle size, thermal processing different levels of fat inclusion and of moisture addition on the amount of gelatinized starch in a corn-soybean broiler diet. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in a three randomized block design consisting of three production series: two particle sizes (coarse: 1041 microns and medium: 743 microns), four fat inclusion levels at the mixer (15, 25, 35, and 45 g/kg of feed), four moisture addition levels in the conditioner (0, 7, 14, and 21g/kg of feed), and two thermal processing treatments (conditioning-pelleting or conditioning-expanding-pelleting) which resulted in 64 different processed feeds. For the determination of the amount of gelatinized starch one feed sample was collected per treatment in each of three production series, totaling three replicates/treatment. Data were transformed using a variation of Box-Cox transformation in order to fit normal distribution (p>0.05). Adding moisture up to 21g/kg of feed in the conditioner linearly increased the amount of gelatinized starch (p 0.05). The conditioner-expander-pelleting treatment of the diets (at 110°C) increased (p 0.05) the degree of starch gelatinization from 32.0 to 35.3 % compared with the conditioner-pelleting treatment (at 80-82°C). The gelatinized starch content increased from 30.2 to 37.2% in the feed (p 0.05) as the particle size increased from medium to coarse. Fat inclusion had a quadratic effect (p 0.05) on starch gelatinization. The degree of starch gelatinization was significantly reduced with fat inclusion levels higher than 35 g/kg of diet. The factors evaluated in this study resulted in interactions and significant effects on degree of starch gelatinization.

Impact of particle size, thermal processing, fat inclusion, and moisture addition on starch gelatinization of broiler feeds

The present study evaluated the effect of feed particle size, thermal processing different levels of fat inclusion and of moisture addition on the amount of gelatinized starch in a corn-soybean broiler diet. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in a three randomized block design consisting of three production series: two particle sizes (coarse: 1041 microns and medium: 743 microns), four fat inclusion levels at the mixer (15, 25, 35, and 45 g/kg of feed), four moisture addition levels in the conditioner (0, 7, 14, and 21g/kg of feed), and two thermal processing treatments (conditioning-pelleting or conditioning-expanding-pelleting) which resulted in 64 different processed feeds. For the determination of the amount of gelatinized starch one feed sample was collected per treatment in each of three production series, totaling three replicates/treatment. Data were transformed using a variation of Box-Cox transformation in order to fit normal distribution (p>0.05). Adding moisture up to 21g/kg of feed in the conditioner linearly increased the amount of gelatinized starch (p 0.05). The conditioner-expander-pelleting treatment of the diets (at 110°C) increased (p 0.05) the degree of starch gelatinization from 32.0 to 35.3 % compared with the conditioner-pelleting treatment (at 80-82°C). The gelatinized starch content increased from 30.2 to 37.2% in the feed (p 0.05) as the particle size increased from medium to coarse. Fat inclusion had a quadratic effect (p 0.05) on starch gelatinization. The degree of starch gelatinization was significantly reduced with fat inclusion levels higher than 35 g/kg of diet. The factors evaluated in this study resulted in interactions and significant effects on degree of starch gelatinization.(AU)

Impact of particle size, thermal processing, fat inclusion, and moisture addition on starch gelatinization of broiler feeds

The present study evaluated the effect of feed particle size, thermal processing different levels of fat inclusion and of moisture addition on the amount of gelatinized starch in a corn-soybean broiler diet. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in a three randomized block design consisting of three production series: two particle sizes (coarse: 1041 microns and medium: 743 microns), four fat inclusion levels at the mixer (15, 25, 35, and 45 g/kg of feed), four moisture addition levels in the conditioner (0, 7, 14, and 21g/kg of feed), and two thermal processing treatments (conditioning-pelleting or conditioning-expanding-pelleting) which resulted in 64 different processed feeds. For the determination of the amount of gelatinized starch one feed sample was collected per treatment in each of three production series, totaling three replicates/treatment. Data were transformed using a variation of Box-Cox transformation in order to fit normal distribution (p>0.05). Adding moisture up to 21g/kg of feed in the conditioner linearly increased the amount of gelatinized starch (p 0.05). The conditioner-expander-pelleting treatment of the diets (at 110°C) increased (p 0.05) the degree of starch gelatinization from 32.0 to 35.3 % compared with the conditioner-pelleting treatment (at 80-82°C). The gelatinized starch content increased from 30.2 to 37.2% in the feed (p 0.05) as the particle size increased from medium to coarse. Fat inclusion had a quadratic effect (p 0.05) on starch gelatinization. The degree of starch gelatinization was significantly reduced with fat inclusion levels higher than 35 g/kg of diet. The factors evaluated in this study resulted in interactions and significant effects on degree of starch gelatinization.

Evaluation of Free-Range broilers using the welfare quality® protocol

Scientific information on the welfare of broilers reared in alternative systems is scarce. The objective of this study was to assess the welfare of free-range broilers using the Welfare Quality® protocol. Free-range broilers reared in ten farms were observed, and measures were made in broilers of five of these farms. The collected data were transformed into scores (0-100), with higher scores indicating better welfare, except for emotional states. Prevalence percentages were calculated for the remaining data. Median (min-max) scores were 81 (63-98) for lameness, 93 (83-99) for hock burn on the farm, 100 (95-100) for plumage cleanliness, 35 (8-70) for podermatitis on the farm, 56 (26-88) for density, 53 (20-53) for dust, 34 (14-67) for litter quality, 93 (41-100) for drinkers, and 100 (100-100) for birds panting or huddling on the farm. The following average (min-max) prevalence percentages were obtained: total mortality 2.0% (1.4-7.2%), culling 0.0% (0.0-2.2%), feed withdrawal time 875 min (715-945 min), water withdrawal time 220 min (170-275 min), dead on arrival at the processing plant 0.00% (0.00-0.01%), broken wings 0%, (0-0%), inefficient stunning 3.9% (1.3-6.7%), pre-stun shock 49.3% (26.7-56.8%), hepatitis 4.5% (1.8-11.0%), bruising 9.3% (6.7-16.7%), and ascites 0% (0-0%). The negative broiler welfare points detected were pododermatitis, litter quality, density, dust, culling, feed withdrawal time, inefficient stunning, pre-stun shock, and hepatitis. The positive points identified were the absence of birds panting or huddling on the farm; low prevalence of lameness, hock lesions, dead on arrival, broken wings, and ascites; good plumage cleanliness scores, and short water withdrawal time.(AU)

Productive consequences of fasting neonatal chicks of different genetic constitutions for growing

The study was designed to evaluate the productive consequences of fasting neonatal chicks obtained from strains genetically divergent for growing. Four hundred eight chicks from three strains, 160 from breeders selected for high growth rate and excellent feed conversion ratio (Cobb 500), 160 from breeders not selected for fast growth (JA57), and 160 from a white egg layer strain (Hy-Line W98) were allotted in a 3 (strain) x 2 (fasting period - 8 and 36h after hatching) factorial arrangement with 5 replicates of 16 chicks each. Immediately after hatching, all chicks had similar (P>0.05) relative yolk sac weights (14.13%, 14.50%, and 15.49% for Hy-Line, Cobb, and JA57, respectively). The yolk sac retractions were proportionally higher for Cobb and JA57 chicks up to 144 h (6 days) after placement, but were not influenced by 36h of feed fasting. At 7 and 14 days of age only Cobb chicks had their body weight and weight gain significantly (P 0.05) depressed by 36h feed fasting after hatching. Results indicate that broiler chicks with intense initial growth rates (Cobb 500) need an outstanding nutritional supply, either from exogenous (feed) or endogenous (residual yolk) sources, to achieve a final weight compatible with their genetic constitution. For slow-growing chicks (Hy-Line), nutritional supplementation via yolk sac seems to be more important than exogenous supply (feed) of nutrients during the neonatal period.

Productive consequences of fasting neonatal chicks of different genetic constitutions for growing

The study was designed to evaluate the productive consequences of fasting neonatal chicks obtained from strains genetically divergent for growing. Four hundred eight chicks from three strains, 160 from breeders selected for high growth rate and excellent feed conversion ratio (Cobb 500), 160 from breeders not selected for fast growth (JA57), and 160 from a white egg layer strain (Hy-Line W98) were allotted in a 3 (strain) x 2 (fasting period - 8 and 36h after hatching) factorial arrangement with 5 replicates of 16 chicks each. Immediately after hatching, all chicks had similar (P>0.05) relative yolk sac weights (14.13%, 14.50%, and 15.49% for Hy-Line, Cobb, and JA57, respectively). The yolk sac retractions were proportionally higher for Cobb and JA57 chicks up to 144 h (6 days) after placement, but were not influenced by 36h of feed fasting. At 7 and 14 days of age only Cobb chicks had their body weight and weight gain significantly (P 0.05) depressed by 36h feed fasting after hatching. Results indicate that broiler chicks with intense initial growth rates (Cobb 500) need an outstanding nutritional supply, either from exogenous (feed) or endogenous (residual yolk) sources, to achieve a final weight compatible with their genetic constitution. For slow-growing chicks (Hy-Line), nutritional supplementation via yolk sac seems to be more important than exogenous supply (feed) of nutrients during the neonatal period.

Performance and carcass characteristics of broiler chickens with different growth potential and submitted to heat stress

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 energy intake on performance and carcass composition of broiler chickens from two different genetic groups

In order to evaluate the effect of energy intake and broiler genotype on performance, carcass yield, and fat deposition, 600 one-day-old male chicks from two different genetic groups (AgRoss 308 - commercial line and PCLC - Embrapa non-improved line) were fed diets with different metabolizable energy level (2950, 3200 and 3450 kcal/kg). A completely randomized experimental design in a 2X3 factorial arrangement with four replications of 25 birds per treatment was applied. In order to ensure different energy intake among treatments within each strain, feed intake was daily adjusted by pair-feeding schemes. AgRoss 308 broilers had better performance and carcass yield, and presented lower abdominal fat deposition rate. In both genetic groups, the highest dietary energy level increased weight gain, heart relative weight, and fat deposition. However, it reduced the difference between AgRoss 308 and PCLC for feed conversion ratio and carcass protein deposition. These findings allow concluding that genetic improvement had a significant effect on broiler energy metabolism, and that the highest performance differences between genetic groups are found when low-energy intake is imposed.

On the use of a probiotic (Bacillus subtilis - strain DSM 17299) as growth promoter in broiler diets

The objective of this experiment was to evaluate the effect of a probiotic (Bacillus subtilis, strain DSM 17299) in broiler diets on feed intake, weight gain, and feed conversion ratio. The experiment included 1,200 male Ross broilers from 1 to 42 days of age. Birds were randomly allocated to 4 treatments, with 10 replicates of 30 birds. The following treatments were applied: T1 - Negative Control (basal diet, with no added growth promoter; T2 - Negative Control + Bacillus subtilis (8 x 10(5) CFUs/g feed); T3 - Negative Control + Bacillus subtilis (3 x 10(5) CFUs/ g de feed) and T4 - Positive Control (avilamycin + anticoccidial from 1 to 35 days of age). At 21, 35, and 42 days of age, there was an increase of antibiotic-free diet intake as compared to the diets with growth promoters (p 0.05), but there was no difference, however, as compared to the diets with probiotic as a growth promoter (p>0.05). The use of growth promoter did not improve weight gain at the studied ages. There was a marked improvement in the feed conversion ratio of broilers fed the diet with antibiotics and of broilers fed the diet with added B. subtilis. It is concluded that the Bacillus subtilis probiotic can be used as a growth promoter in broiler diets.

On the use of a probiotic (Bacillus subtilis - strain DSM 17299) as growth promoter in broiler diets

The objective of this experiment was to evaluate the effect of a probiotic (Bacillus subtilis, strain DSM 17299) in broiler diets on feed intake, weight gain, and feed conversion ratio. The experiment included 1,200 male Ross broilers from 1 to 42 days of age. Birds were randomly allocated to 4 treatments, with 10 replicates of 30 birds. The following treatments were applied: T1 - Negative Control (basal diet, with no added growth promoter; T2 - Negative Control + Bacillus subtilis (8 x 10(5) CFUs/g feed); T3 - Negative Control + Bacillus subtilis (3 x 10(5) CFUs/ g de feed) and T4 - Positive Control (avilamycin + anticoccidial from 1 to 35 days of age). At 21, 35, and 42 days of age, there was an increase of antibiotic-free diet intake as compared to the diets with growth promoters (p 0.05), but there was no difference, however, as compared to the diets with probiotic as a growth promoter (p>0.05). The use of growth promoter did not improve weight gain at the studied ages. There was a marked improvement in the feed conversion ratio of broilers fed the diet with antibiotics and of broilers fed the diet with added B. subtilis. It is concluded that the Bacillus subtilis probiotic can be used as a growth promoter in broiler diets.

Effect of energy intake on performance and carcass composition of broiler chickens from two different genetic groups

In order to evaluate the effect of energy intake and broiler genotype on performance, carcass yield, and fat deposition, 600 one-day-old male chicks from two different genetic groups (AgRoss 308 - commercial line and PCLC - Embrapa non-improved line) were fed diets with different metabolizable energy level (2950, 3200 and 3450 kcal/kg). A completely randomized experimental design in a 2X3 factorial arrangement with four replications of 25 birds per treatment was applied. In order to ensure different energy intake among treatments within each strain, feed intake was daily adjusted by pair-feeding schemes. AgRoss 308 broilers had better performance and carcass yield, and presented lower abdominal fat deposition rate. In both genetic groups, the highest dietary energy level increased weight gain, heart relative weight, and fat deposition. However, it reduced the difference between AgRoss 308 and PCLC for feed conversion ratio and carcass protein deposition. These findings allow concluding that genetic improvement had a significant effect on broiler energy metabolism, and that the highest performance differences between genetic groups are found when low-energy intake is imposed.

Performance and carcass characteristics of broiler chickens with different growth potential and submitted to heat stress

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.

Methionine sources do not affect performance and carcass yield of broilers fed vegetable diets and aubmitted to cyclic heat stress

The supplementation of vegetal diets with L-methionine (100% molar), methionine hydroxyl analogue (HMB) (88% molar) or DL-methionine (99% molar) was compared as to the performance of broilers allocated in cages and submitted to cyclic heat stress (CHS). The trial was carried out from 21 to 42 days of age. Two levels of synthetic methionine were supplemented for each methionine source (0.1 or 0.3 %), and the control treatment was not supplemented with synthetic methionine (negative control). Statistical analyses included the negative control treatment or were performed in a 3 x 2 factorial design (sources x levels). Addition of synthetic methionine to the basal level containing 0.63 % of total sulphur amino acids significantly improved feed conversion (FC) independent of the source. On the other hand, improvements in weight gain (WG) and body weight (BW) were more consistent comparing the negative control to HMB-supplemented treatments. Factorial analysis showed better FC for L-Met compared to DL-Met, whereas HMB showed intermediate results. The supplementation level of 0.3% methionine showed better FC than 0.1%. Methionine levels or sources had no effects on carcass, yields of cuts or feathering results. Therefore, results of DL-Met and HMB added to vegetal-based diets in comparable molar terms promoted similar performance in broilers under CHS conditions.

Methionine sources do not affect performance and carcass yield of broilers fed vegetable diets and aubmitted to cyclic heat stress

The supplementation of vegetal diets with L-methionine (100% molar), methionine hydroxyl analogue (HMB) (88% molar) or DL-methionine (99% molar) was compared as to the performance of broilers allocated in cages and submitted to cyclic heat stress (CHS). The trial was carried out from 21 to 42 days of age. Two levels of synthetic methionine were supplemented for each methionine source (0.1 or 0.3 %), and the control treatment was not supplemented with synthetic methionine (negative control). Statistical analyses included the negative control treatment or were performed in a 3 x 2 factorial design (sources x levels). Addition of synthetic methionine to the basal level containing 0.63 % of total sulphur amino acids significantly improved feed conversion (FC) independent of the source. On the other hand, improvements in weight gain (WG) and body weight (BW) were more consistent comparing the negative control to HMB-supplemented treatments. Factorial analysis showed better FC for L-Met compared to DL-Met, whereas HMB showed intermediate results. The supplementation level of 0.3% methionine showed better FC than 0.1%. Methionine levels or sources had no effects on carcass, yields of cuts or feathering results. Therefore, results of DL-Met and HMB added to vegetal-based diets in comparable molar terms promoted similar performance in broilers under CHS conditions.