Ali Merati Fashi1, Sara Mirzaie Goudarzi *1 
, Ali asghar Saki1, Abbas Farahavar1, Zahra Jahanbakhsh Rad1
, Ali asghar Saki1, Abbas Farahavar1, Zahra Jahanbakhsh Rad1
1- Department of Animal Sciences, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
Abstract: (856 Views)
Extended abstract
Background: Agricultural by-products can be used as part of the diet; they also reduce animal feed costs, which reduces the risks of environmental pollution. The advantage of agricultural by-products, including garlic and onion peel, is due to their abundance, availability, renewability, and non-competitiveness with food. Garlic peels contain lignocellulosic and polyphenol compounds. Onion peels have been identified as a source of flavoring compounds, insoluble fiber, non-structural carbohydrates, and polyphenols. Therefore, this experiment aimed to study the effect of different levels of garlic and onion peels on performance, gastrointestinal tract characteristics, blood parameters, and meat quality in broiler chickens.
Methods: In total, 250-day-old Ross 308 broiler chickens were modulated in five treatments, five replicates, and 10 chickens in each from 1 to 42 days of age in a completely randomized design in the current study. The experimental treatments included 1) control (corn and soybean meal), 2) control + 2% garlic peel, 3) control + 4% garlic peel, 4) control + 2% onion peel, and 5) control + 4% onion peel. First, a basal diet was formulated according to Ross 308 broiler nutrition specifications (2022) based on the standardized ileum digestible amino acid (SID) and ideal protein pattern. For this purpose, the basal diet based on corn- soybean meal was formulated for starter, grower, and finisher periods from 1 to 42 days of age. Then, the basal diet was diluted by 2 or 4 % of garlic or onion peel, respectively. Feed intake and body weight were recorded weekly and cumulatively. Body weight gain (BWG) and feed conversion ratio (FCR) were calculated based on these data as hen/day. At the end of the experiment (42 days of age), one chicken in each replicate was killed to measure the carcass and the gastrointestinal tract (GIT) characteristics. The measured parameters were carcass weight, breast and thigh, whole weight of GIT, proventriculus, gizzard, pancreas, liver, duodenum, jejunum, ileum, cecum, length of the small intestine, and cecum. Also, one bird per replicate (n = 5) was killed by asphyxiation with CO2, and then the pH of the crop, proventriculus, gizzard, duodenum, jejunum, ileum, and cecum digesta were measured by a pH meter.
To examine blood parameters, blood was collected from the same chickens selected for slaughter, and the serum glucose, cholesterol, and triglyceride concentrations were measured using a Pars-Azmon kit by a spectrophotometer. The concentrations of alanine aminotransferase and aspartate aminotransferase enzymes were determined using the Pars-Azmon kit by an autoanalyzer. In addition, meat quality parameters, including thigh and breast meat color, as well as dry matter, cooking loss, and water holding capacity in the breast meat, were tested immediately after slaughter. The meat color indices, including lightness (L*), redness (a*), and yellowness (b*), were evaluated immediately at zero and 24 hours after slaughter by a Hunter Lab device. The data were statistically analyzed by SAS statistical software and the general linear model procedure. Means were compared by Tukey's test at the 5% probability level.
Results: The growth performance of broilers was not affected by treatments in the starter and finisher periods (P > 0.05). However, the inclusion of 2 and 4% onion peel in the diet significantly decreased feed intake and BWG in the grower period and in the whole rearing period (P < 0.05); however, the FCR was not affected by the treatment (P > 0.05). Carcass yield and thigh or breast percentage were not affected by the dilution of the diet in response to garlic and onion peel (P > 0.05). The inclusion of garlic and onion peel in the diet tended to significantly increase the whole weight of the GIT (P = 0.08). A significantly increased relative weight of the gizzard was observed by feeding broiler chickens with a diet containing 4% onion peel (P < 0.05). The pH of different parts of the GIT was not affected by treatments, except in the crop, which significantly decreased in chickens fed with 4% onion peel (P < 0.001). Serum cholesterol and triglyceride concentrations were significantly decreased in the treatments containing garlic and onion peel levels compared with the control group (P < 0.001). The thigh meat redness index (a*) at zero time after slaughter decreased in the birds fed with 2% and 4% garlic peel compared with the control treatment (P < 0.05), but this trait was not affected at 24 hours after slaughter (P > 0.05). A significantly decreased brightness index (L*) of the breast meat was observed by the inclusion of 4% garlic peel in the diet (P < 0.05). However, dry matter, cooking loss, and water holding capacity were not affected by treatments in this respect (P > 0.05).
Conclusion: The general results of the current experiment show that supplementation up to 4% garlic peel could be recommended in the diet of broiler chickens for GIT development without any negative effect on performance. Broilers fed with different levels of garlic and onion peel presented lower blood cholesterol and triglyceride concentrations and were similar in carcass yield compared to the control group.
Background: Agricultural by-products can be used as part of the diet; they also reduce animal feed costs, which reduces the risks of environmental pollution. The advantage of agricultural by-products, including garlic and onion peel, is due to their abundance, availability, renewability, and non-competitiveness with food. Garlic peels contain lignocellulosic and polyphenol compounds. Onion peels have been identified as a source of flavoring compounds, insoluble fiber, non-structural carbohydrates, and polyphenols. Therefore, this experiment aimed to study the effect of different levels of garlic and onion peels on performance, gastrointestinal tract characteristics, blood parameters, and meat quality in broiler chickens.
Methods: In total, 250-day-old Ross 308 broiler chickens were modulated in five treatments, five replicates, and 10 chickens in each from 1 to 42 days of age in a completely randomized design in the current study. The experimental treatments included 1) control (corn and soybean meal), 2) control + 2% garlic peel, 3) control + 4% garlic peel, 4) control + 2% onion peel, and 5) control + 4% onion peel. First, a basal diet was formulated according to Ross 308 broiler nutrition specifications (2022) based on the standardized ileum digestible amino acid (SID) and ideal protein pattern. For this purpose, the basal diet based on corn- soybean meal was formulated for starter, grower, and finisher periods from 1 to 42 days of age. Then, the basal diet was diluted by 2 or 4 % of garlic or onion peel, respectively. Feed intake and body weight were recorded weekly and cumulatively. Body weight gain (BWG) and feed conversion ratio (FCR) were calculated based on these data as hen/day. At the end of the experiment (42 days of age), one chicken in each replicate was killed to measure the carcass and the gastrointestinal tract (GIT) characteristics. The measured parameters were carcass weight, breast and thigh, whole weight of GIT, proventriculus, gizzard, pancreas, liver, duodenum, jejunum, ileum, cecum, length of the small intestine, and cecum. Also, one bird per replicate (n = 5) was killed by asphyxiation with CO2, and then the pH of the crop, proventriculus, gizzard, duodenum, jejunum, ileum, and cecum digesta were measured by a pH meter.
To examine blood parameters, blood was collected from the same chickens selected for slaughter, and the serum glucose, cholesterol, and triglyceride concentrations were measured using a Pars-Azmon kit by a spectrophotometer. The concentrations of alanine aminotransferase and aspartate aminotransferase enzymes were determined using the Pars-Azmon kit by an autoanalyzer. In addition, meat quality parameters, including thigh and breast meat color, as well as dry matter, cooking loss, and water holding capacity in the breast meat, were tested immediately after slaughter. The meat color indices, including lightness (L*), redness (a*), and yellowness (b*), were evaluated immediately at zero and 24 hours after slaughter by a Hunter Lab device. The data were statistically analyzed by SAS statistical software and the general linear model procedure. Means were compared by Tukey's test at the 5% probability level.
Results: The growth performance of broilers was not affected by treatments in the starter and finisher periods (P > 0.05). However, the inclusion of 2 and 4% onion peel in the diet significantly decreased feed intake and BWG in the grower period and in the whole rearing period (P < 0.05); however, the FCR was not affected by the treatment (P > 0.05). Carcass yield and thigh or breast percentage were not affected by the dilution of the diet in response to garlic and onion peel (P > 0.05). The inclusion of garlic and onion peel in the diet tended to significantly increase the whole weight of the GIT (P = 0.08). A significantly increased relative weight of the gizzard was observed by feeding broiler chickens with a diet containing 4% onion peel (P < 0.05). The pH of different parts of the GIT was not affected by treatments, except in the crop, which significantly decreased in chickens fed with 4% onion peel (P < 0.001). Serum cholesterol and triglyceride concentrations were significantly decreased in the treatments containing garlic and onion peel levels compared with the control group (P < 0.001). The thigh meat redness index (a*) at zero time after slaughter decreased in the birds fed with 2% and 4% garlic peel compared with the control treatment (P < 0.05), but this trait was not affected at 24 hours after slaughter (P > 0.05). A significantly decreased brightness index (L*) of the breast meat was observed by the inclusion of 4% garlic peel in the diet (P < 0.05). However, dry matter, cooking loss, and water holding capacity were not affected by treatments in this respect (P > 0.05).
Conclusion: The general results of the current experiment show that supplementation up to 4% garlic peel could be recommended in the diet of broiler chickens for GIT development without any negative effect on performance. Broilers fed with different levels of garlic and onion peel presented lower blood cholesterol and triglyceride concentrations and were similar in carcass yield compared to the control group.
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