Poultry Science Journal
Volume:8 Issue: 1, Winter-Spring 2020

The intron-exon structure of Khorasan native fowl interleukin-2 (IL-2) was investigated. For this purpose, twenty chickens were selected from the Native Fowl Breeding Station of Khorasan province, and genomic DNA was extracted using a modified conventional DNA extraction protocol. An 875 bp fragment of IL-2 was successfully amplified, including a small part of the promoter, exon 1, intron 1, and exon 2. To report a novel mutation in IL-2, PCRsequencing techniques were applied to the gene obtained from Khorasan native fowls. Then, the sequences were compared to evaluate gene mutations using CLC Main Workbench V. 5.5. The I-TASSER server was used to predict the 3-dimensional structure and function of protein molecules from amino acid sequences. The results of the comparison showed mutations in the DNA fragments of the sample birds, which caused changes in the amino acid content of IL-2. Substitutions at points 733, 738, 744, and 794 bp in the sequence were for C/A, A/T, C/A, and C/T, respectively. The translation of nucleotide to protein using BLASTx in the NCBI revealed that nucleotide substitutions caused three amino acid substitutions including A/E, R/W, and P/T.

Two trials were conducted to study the effect of multi-steps phase-feeding (PF) program on growth performance of broiler chickens from 1 to 24 and 1 to 39 d of age. The control group was the nutrient recommendation of Aviagen (2019) with a three-step PF program (1-10, 11-24 and 25-39 d of age). In the first trial, the control group was compared with an eight-step PF program (PF8), and in the second trial, it was compared with a thirteen-step PF program (PF13). A gradual increase of metabolizable energy and a decrease of crude protein and amino acids were applied in PF8 and PF13 over time of life. Treatments were replicated in 5 pens of 15 males per each. Feed conversion ratio, lysine intake efficiency and feed cost efficiency were improved (P ≤ 0.05) by the PF8 and PF13. In trial 1 (during 1 to 24 and 1 to 39 d of age) and trial 2 (during 1 to 39 d of age), energy intake efficiency was increased (P ≤ 0.05) by the multi-step PF program. In trial 1 (during 1 to 24 and 1 to 39 d of age) and trial 2 (during 1 to 24 d of age), average daily gain was not improved (P > 0.05) by the multi-step PF program compared to the control group; however, the PF13 increased (P ≤ 0.05) average daily gain during 1 to 39 d of age. In conclusion, the current study shows the eight-step or thirteen-step phase feeding program improves feed conversion ratio compared to the current commercial three-step feeding program. Meanwhile, the thirteen-step phase feeding program increases weight gain from 1 to 39 d of age.

This study was conducted to investigate the effects of dietary inclusion of the encapsulated thyme essential oil (TEO), oregano essential oil (OEO) mixture and probiotic on growth performance, immune response and intestinal morphology of broiler chickens. A total of 490 one-day-old Ross 308 broiler chicks were randomly divided into seven treatments consisting of five replicates (n=14). Birds were fed with 1) basal diet (control), and a basal diet containing; 2) 10 mg Avilamicine antibiotic, 3) 200 mg/kg encapsulated TEO+OEO mixture, 4) 200 mg/kg non-capsulated TEO+OEO mixture, 5) Pronigeb® (probiotic), 6) Pronigeb® with 200 mg/kg non-capsulated TEO+OEO mixture and 7) Pronigeb® with 200 mg/kg encapsulated TEO+OEO mixture. Results revealed that birds fed diet containing antibiotic, encapsulated TEO+OEO mixture with and without probiotic had significantly higher body weight gain (BWG) compared with control and non-capsulated TEO+OEO mixture groups on day 42 (P < 0.05). Dietary inclusion of TEO+OEO in capsulated form and also in along to probiotic increased humoral immunity in broiler chickens compared with other groups (P < 0.05). Birds fed the diet supplemented with different types of additives showed significantly higher dinitrochlorobenzene (DNCB) compared with the control group at 32 days of age (P < 0.05). Dietary inclusion of the encapsulated EOs with and without probiotic both significantly increased villus length and villus width in comparison to other groups (P < 0.05). The highest and lowest ratios were observed for the control group and probiotic+encapsulated TEO+OEO group respectively. These results indicate that feeding birds with diet containing encapsulated EOs alone or together with probiotic could improve BWG, immune responses and intestinal morphology in broiler chickens.

This study evaluated the effect of a combination of mannan-oligosaccharides (MOS) and microbial phytase (MP) on growth performance, some blood biochemical metabolites, intestinal morphology and cecal microbial population of ROSS 308 broiler chickens from d 0 to 35 of age. A total of 200 one-dayold broiler chickens (mixed sex) were randomly distributed into four treatments with five replicates and 10 birds per each. The dietary treatments included a basal diet, the basal diet supplemented with MOS (as 2 g/kg of diet), MP (as 100 g/t Phyzyme XP 5000), and the combination of MOS and MP (MOS+MP). Supplementation of MOS+MP improved feed conversion ratio and body weight gain of broilers compared with the control group (P < 0.05). Dietary treatments had no significant effect on carcass traits. In the intestinal morphometric indices, villus length was greater in the birds which received MP individually or in combination with MOS (P < 0.05). Supplementation of MP, MOS or MOS+MP increased serum concentration of calcium in the broilers compared with control treatment (P < 0.05). Broiler chickens fed diets containing MOS+MP had lower numbers of E. coli, but higher count of Lactobacilli rather than control group (P < 0.05). Based on these results, it is concluded that dietary supplementation of MP in combination with MOS improved growth performance and intestinal microbial ecosystem of broiler chickens.

The primary aim of this study was to assay the influence of dietary Ca sources and levels on performance, egg quality indices, and selected blood variables of laying hens. A total of 192 Bovanz commercial layers were distributed to 6 dietary treatment groups with 4 replicates and 8 birds in each replicate. The experimental diets were iso-caloric and iso-nitrogenous, but they were different in the concentrations of available phosphorus and total calcium (0.29 and 3.8% or 0.31 and 4.0%, respectively) and in the origination of applied calcium (limestone A, limestone B, and oyster shell). Although the amounts of calcium and phosphorus were different among the diets, the ratio between them was the same in all diets. The results indicated that dietary treatments had not any significant effect on feed intake, feed conversion ratio, egg production, egg weight, egg mass, and body weight gain of hens. Egg quality indices were not influenced by dietary treatments in both egg sampling, except for eggshell weight and shell weight ratio, which decreased as a reduction of the dietary Ca level in the second period. The rate of broken, soft-shell and unmarketable eggs laid by the hens fed a diet containing lower Ca was increased. There was no significant effect of dietary Ca source and concentration on blood Ca and P, while serum ALP activity decreased significantly with increasing the amount of calcium in the diet. There was also, no interaction between Ca source and concentration for any of these parameters. Although all Ca sources applied in this experiment could supply the hens with sufficient Ca, the rate of unmarketable eggs decreased by using a higher concentration of Ca.

A feeding trial was carried out to investigate the effects of lecithin on growth performance, nutrient digestibility, lipid profile, carcass characteristics and meat quality of broiler chickens. A total of 240 oneday- old male broiler chicks (Cobb 500) were obtained from a local hatchery and raised for 42 days. The chicks were divided into 5 dietary treatments. The diets supplemented with prilled palm fat + 2% lysolecithin (PFL) replacing palm oil at 0%, 1%, 3%, 5%, and 7%. Each treatment group was divided into 6 replicates and 8 chicks per each replicate. Feed and water were offered ad libitum to the birds. The individual body weight and the feed intake for each replicate were recorded. In the finisher and overall periods, the findings showed that body weight gain (BWG) was significantly (P < 0.05) higher in birds fed 1% PFL compared to those birds fed 5% or 7% PFL. The nutrient digestibility was significantly (P < 0.05) higher in broiler supplemented with 1% PFL compared to the rest of the treatment groups. However, no significant differences were observed against 3% PFL for crude fat digestibility. The breast meat color was within the normal range in broiler fed 1% PFL than those fed higher ratios of PFL. The study revealed that supplementation of PFL at 1% substantially improved nutrient digestibility as well as BWG and FCR during the overall period.

This study examined the effects of various levels of dietary encapsulated choline chloride (ECC) on growth performance, carcass characteristics, serum and liver lipids content in Ross 308 broilers. A total of 480 day-old broilers were assigned to eight dietary treatments with six replicates of 10 birds each from 1 to 21 days of age. Eight experimental diets were provided from a basal non-added choline chloride diet as follow: six diets were made by the addition of ECC at the rate of 300, 600, 900, 1200, 1500 and 1800 mg/kg and a negative and a positive control diet with zero and 1500 mg/kg commercial choline chloride (CCC), respectively. The body weight gain, feed intake, choline chloride (CC) intake, live body weight, as well as carcass, breast muscle, thigh muscle, and liver weights were linearly (P < 0.05) related to the dietary levels of ECC. Dietary supplementation of ECC at the levels of 1200 and 1500 mg/kg decreased (P = 0.014) liver total lipid percentage, compared to those fed the negative control diet. The birds fed diets containing 900 and 1200 mg ECC/kg had lower liver triglyceride concentration than those fed negative control diet (P = 0.001). Furthermore, supplemented ECC at the levels of 1200 and 1800 mg/kg, led to an increase (P = 0.006) in the concentration of phospholipid in the liver. The ECC requirements were estimated at 1335.1, 1371.6 and 1353.3 mg/kg of diet for maximizing body weight gain, carcass weight, and breast weight, respectively (P < 0.001). It is concluded that the ECC may be used as an alternative to CC in the diet at the rate of 1500 mg/kg with no adverse effect on productive performance, breast and thigh muscle weight, and liver fat content in broilers.

Flock health monitoring program is an important system, used in the poultry industry worldwide to minimize the production cost, detect clinical and subclinical diseases and acquire data to make comparisons among the farms and identify the future research area. The present study was aimed to investigate the broiler health status through a flock health monitoring program using the lesion scoring method. For this purpose, a total of 540 broiler birds were collected from four different places from January to December 2017 and necropsied. Five body systems including gastrointestinal, respiratory, immune, skeletal, and integumentary were monitored with their 33 parameters during the study period. All the scores obtained from different parameters were analyzed and summarized. Among the body systems, lesion scores percentages were more prevalent in the parameters of the gastrointestinal, respiratory, and immune systems. Regarding age groups, 2nd (0-84.4%) and 3rd weeks (0- 78.3%) had most of lesion scores percentage compared to 4th weeks (0-70.6%). With respect to season, lesion scores percentages were highest in summer (0-87.2%) and winter season (0-76.7%) respectively than monsoon season (0- 68.3%). Based on different scores, zero was scored by the most number of birds ranged from 22.6-100%, while one was scored in 0-66.9%, two in 0- 15.2%, three in 0-5.9%, and four in 0-0.4% of birds, respectively. Flock health monitoring program is a mirror of flock health status that can be a great alternative for the poultry industry and manager. Thus, the flock monitoring program mainly emphasizes poultry health which can be a good approach for future disease prevention.

Chitin is the most abundant natural biopolymer that can be converted to chitosan, which has various biomedical applications. This study was conducted to investigate the antioxidant activity of chitosan extracted from shrimp shells on body weight of broiler chickens. The study comprised three experiments. In experiment 1, shrimp (Penaeus merguiensis) shells were demineralized using HCL (1N), deproteinized using NaOH (1N), decolorized using acetone, and deacetylated using 50% NaOH. The antioxidant potencies of chitosan and vitamin C were compared by their abilities to scavenge 1, 1-diphenyl-2- picrylhydrazyl (DPPH) free radicals. The DPPH free radical scavenging activity of chitosan at varying concentrations (1-20 mg/ml) ranged between 34.59 and 87.11%, whereas that of 1 mg/ml of vitamin C was 91.1%. In experiment 2, six dietary treatments containing varying concentrations of chitosan (0, 0.125, 0. 25, 0.5, 1, and 2 g/kg) were allocated randomly to 60 male broiler chicks from 10 to 42 days of age. Chitosan at varying concentrations had no significant effect on the body weight, but it significantly decreased the MDA level in breast meat (p<0.05). In experiment 3, a total of 20 male broiler chickens were divided into two groups (n=10) and were fed a corn-soybean basal diet with or without chitosan for 42 days. On days 35 and 38, five chickens from each group were treated with carbon tetrachloride (CCL4) at 1 mL/kg body weight to induce oxidative stress. Administration of CCL4 significantly decreased body weight and increased AST and ALT activities, which are indicators of liver damage, on day 42, whereas chitosan improved and normalized body weight and enzyme activity (p<0.05). The results suggested that chitosan extracted from shrimp shells exhibits antioxidant effects by increasing the shelf life of the meat and normalizing the body weight of the broilers as well as serum AST and ALT enzyme activities.

The purpose of this experiment was to investigate the effect of one-week feeding of flaxseeds (rolled/extruded) on performance, n-3 fatty acids and oxidative stability of meat in broiler chickens. Seven pelleted diets (36-42d) were provided in a 3×2 factorial arrangement with three flaxseed levels (5, 10, and 15%) and two processing methods (rolled/extruded) and a zero flaxseed control diet. Before the main trial, a total collection method experiment showed that the replacement of 10 and 15% of rolled/extruded flaxseeds in broiler diets caused a marked reduction in the apparent metabolizable energy (AMEn) as compared to those fed basal or 5% flaxseed replaced diets. In the main trial; weight gain was significantly reduced when flaxseed was supplemented at the level of 15%. Lipid peroxidation in thigh meat of birds fed diets contained zero or 5% flaxseed were lower than those fed diet with 10 or 15% flaxseed. The inclusion of flaxseed in the last week of feeding finisher diet linearly reduced the concentrations of saturated fatty acids and monounsaturated fatty acids, in the thigh and breast meat, respectively, whereas, the n-3 and n-3:n-6 ratio linearly increased in both thigh and breast meat. Processing methods of flaxseed did not affect the bird’s performance and fatty acid profiles in meat. It is concluded that the replacement of diets with 5% flaxseed did not affect the AMEn of diet. Feeding diets containing flaxseed for one week before marketing can reduce saturated FA and increase n-3 and n-3: n-6 ratio in meat, but the adverse effect on performance appeared when diets contained 15% flaxseed.

This study was performed to investigate the effects of dietary threonine (Thr). level on performance, metabolizable energy, intestinal morphology, and immune system in coccidian–infected broiler chickens. The diets contained: 88%, 100% (Non challenged (NC) and challenged control (PC)), 112%, 124%, and 136% of Thr requirement according to Cobb 500 recommendation and fed during grower (pre challenged) and finisher (post challenged) periods. On d 23 (end of grower period), each bird received 0.5 mL of distilled water or received around 24000 sporulated oocysts. On d 23 and 31, one bird per replicate was slaughtered to measure the performance criteria. Mean dietary apparent metabolizable energy corrected for nitrogen (AMEn) and digestible energy were greater in NC birds than the challenged birds fed on 88% or 100% Thr diets. Feed intake and blood parameters were not significantly influenced by increasing levels of Thr in the diet. Compared with unchallenged birds with coccidia (NC), the growth performance, morphological parameters (not crypt depth), and immune responses decreased (P < 0.05) in the birds (PC) that were challenged with coccidia, and oocyte numbers were enhanced. Growth performance, jejunal morphology, and immune responses improved and oocyte count decreased in coccidian- challenged birds fed on the diets with greater levels of Thr (P < 0.05). Feeding the challenged birds with the diet containing greater levels of Thr improved (P < 0.05) their growth performance, morphology, and immune responses and decreased oocyte number. The birds fed on the diet with 124% Thr demonstrated a similar response as the NC birds. Increased diet Thr level linearly increased average daily gain and decreased feed conversion ratio in the grower and the whole experimentation periods. The AMEn and digestibility of crude protein were enhanced linearly Thr level increased in coccidian-challenged birds. It is concluded that diets containing 124% of Thr recommendation led to the greatest efficacy on the intestinal immuneresponse and normal growth maintenance of the birds contaminated with coccidia.

One hundred forty four 10-day old male Arbor Acres (320±5g) broiler chicks were used to compare the responses in liver function to dietary supplementation of milk thistle (Silybum marianum), artichoke (Cichorium intybus) and olive (Olea europaea) extracts with gemfibrozil and atorvastatin, in broiler chickens fed with a lipogenic diet. Birds raised in the standard experimental conditions and received a pelleted grower diet (control) supplemented with milk thistle (250 mg/kg), artichoke (200 mg/kg), olive (150 mg/kg) extracts, atorvastatin (20 mg/kg) and gemfibrozil (1800 mg/kg) up to day 42 of age. Liver weight and liver fat parentages were 1.62 and 6.04%, respectively, in the birds fed with the un-supplemented basal diet (control) and modified by +0.21 and -2.13, +0.11 and -1.21, +0.14 and -1.40, -0.07 and -2.36, +0.07 and -0.38% in the birds received milk thistle, artichoke, olive extracts, gemfibrozil, and atorvastatin, respectively. The milk thistle-added diet elicited a significant reduction in serum activity of aspartate aminotransferase and alanine aminotransferase at day 35 of age. Dietary olive extract at 150 mg/kg reduced liver fat at day 35 of age compared with those grown on the basal diet (P < 0.05). The serum concentration of triglycerides was lower (P < 0.05) in the birds fed with diets enriched with artichoke (34.86 mg/dL) and olive extract (40.63 mg/dL) compared with those fed with the supplemented control diet at day 35 of age. It was concluded that milk thistle exerted greater promising hepatoprotective effects compared with other remedies. Gemfibrozil exhibited a greater hepatoprotective and blood lipid-lowering effect than atorvastatin in broiler chicken.