Heshmatollah Khosravinia

Effect of the slow (K) or rapid (k +) feathering gene on carcass-related traits of broiler chickens selected for breast and thighs weight

This study was undertaken to evaluate the impact of slow/rapid feathering sex-linked gene on carcass weight (CW) and yield (CY) as well as carcass main parts in an experimental colored broiler flock employing to evaluate the response to selection for breast and thighs weight with imposing restriction against low value portions of carcass over three generations. Random samples of the birds were slaughtered to evaluate the carcass traits at 42 days of age. Cut up yield was determined by partitioning each carcass to breast, thighs as high value parts and wings, neck, rack and saddle as low value portions (LVP). Live body weight (BW; 42d) and legs yield (LY) as a proportion of carcass weight (as % CW) were significantly greater for k+k+/k+W genotypes compared to K-/KW bearing birds (P < 0.05). Intersex t test comparisons revealed significant superiority of the k+k+ genotype over K- in male birds for LY (as % CW) and LY (as % BW) (P < 0.05). Interfamily analysis for eight larger half-sib families revealed infrequent superiority of K-/KW bearing birds over their sibs with the alternate genotype for breast yield (BrY; as % CW), legs weight (LW) and LY (as % CW) in two families. Interfamily and interfemales analysis for seven larger half-sib families showed highly significant superiority for k+W birds in LW (as % CW), BW and LVW in two families (P < 0.01). Considering feathering rate as a fixed effect (KW vs. k+W) to analyze the females data revealed significantly greater means for fast feathered females (k+W) for BW, CW, breast weight, LW and LVW than the alternate genotype (P < 0.05). It is concluded that in the today straight-run broiler flocks with numerous influencing factors of margin effects, and with increasing demands for uniformity of carcass market where sexable day-old chicks are not of interest, to launch the fast feathering gene (k+) could be of positive economic consequences in broiler production.

Effects on Productive Performance, Tibia Calcium and Phosphorous Retention, and Liver Enzymes Activity of Acidified and Alkalinized Diets in Broiler Chicken

Abstract A 35-day experiment was carried out to study the effects of acidified and alkalinized diets on zootechnical indices, tibial calcium and phosphorous retention, bone mineralization and liver enzymes activity using 250 Ross 308 male broiler chicks. Five treatments consisting of a control diet (CD), CD acidified using 10, 20 and 30 g/kg citric acid (CA) and CD alkalinized with Ca (OH)2 (8.9 g/kg in growth period and 8.6 g/kg in finisher period) were examined in 5 replicates of 10 birds each from day 7 up to day 42 of age. Inclusion of 30 g/kg CA significantly increased body weight, average daily gain (ADG), average daily feed intake (ADFI), feed efficiency, tibia ash, tibia Ca content, at day 42 of age (P<0.05). Serum alkaline phosphatase and lactate dehydrogenase activities were elevated in the birds fed with the 30 g/kg CA-treated diet at day 42 of age (P<0.05). Alkalinized diet significantly reduced ADFI, tibia ash, tibial P and Ca contents, bone breaking strength and plasma Ca concentration (P<0.05). It was concluded that the diet acidified with 30 g/kg CA promoted productive performance and tibia mineralization in broiler chicken. Alkalinized diet suppressed growth performance of the birds perhaps through disrupted mineral absorption and altered liver enzymes activity.

Effects of substituting fish meal with poultry by-product meal in broiler diets on blood urea and uric acid concentrations and nitrogen content of litter

This study was carried out to investigate the effects of dietary substitution of fish meal (FM) with poultry by-product meal (PBM) at 0%, 25%, 50%, 75% and 100% using 360, 1-day-old Arian broiler chicken. The birds were randomly allocated to 30 pens (at density of 0.08 m2/bird) in an open system partially controlled house. The chicks were raised under a photo regimen of 23:1h light to darkness up to 42 days. The five dietary treatments were offered to six replicates of 12 chicks each. Data on productive performance, serum concentrations of urea and uric acid and pH, moisture and nitrogen content of litter were collected at different ages. The mean weight gain, feed intake and feed conversion ratio were significantly decreased in the birds fed on diets containing more than 50% PBM compared to the control birds during days 1–21 of age (P < 0.01). Replacement of FM at different levels with PBM significantly affected either serum urea or uric acid concentrations (P < 0.05). The serum urea and uric acid concentrations was lower in the birds that received 100%-PBM containing diets. The mean nitrogen content of litter was similar among the experimental diets while the moisture content of litter tended to be lower for the birds fed on diets containing 25% PBM compared to the other birds (P < 0.10). No differences in litter pH were pointed out for dietary treatments. Treating the litter samples by Alum significantly increased their pH values (P < 0.01). The results suggest that, substitution of FM with PBM at different levels had no considerable impact on nitrogen contents of litter.

Physiological Responses of Newly Hatched Broiler Chicks to Increasing Journey Distance During Road Transportation

This study was conducted to examine the effects on weight loss (WL), residual yolk (RY) utilization and serum biochemical parameters of transport distance (TD) in newly hatched broiler chicks. Just after hatching, 200 Ross 308 broiler chicks were traveled over 1000 km. At hatchery and after 200, 400, 600, 800 and 1000 km journey, a random sample of 20 birds were killed for blood collection, WL and yolk weight assessment. Live weight decreased linearly by 0.42 and 0.48 g per 100 km of journey in males and female chicks, respectively. Yolk sac residual utilized by 0.071 and 0.069 g per 100 km of travel in males and females chicks, respectively, over journey distances up to 800 km. Extended journey from 800 to 1000 km caused a great decline of 0.51 and 0.58 g per 100 km in yolk weight in male and female chicks, respectively. Serum Ca concentration reduced in TDs up to 400 km, then increased for longer journeys (P<0.05). Over 1000 km journey, serum GLU level of 196.24 mg/dL at hatchery was decreased to 117.31 mg/dL at the end of journey. Serum urea, uric acid and cholesterol concentrations were increased with the extended TDs (P<0.05). In conclusion increasing transportation distance causes intensified physiological stress in broiler chicks with varying effect on different stress indicators. Stress indicators in newly hatched chicks in transit may differ from those proposed for replaced chicks and the broiler chicken at later ages.

Productive performance, nutrient digestibility and intestinal morphometry in broiler chickens fed corn or wheat-based diets supplemented with bacterial- or fungal-originated xylanase

Abstract An experiment was conducted to evaluate effects of dietary supplementation of a corn- or a wheat-based diet with two sources of exogenous xylanase (fungal or bacterial originated) on productive performance, ileal nutrients digestibility, nitrogen-corrected apparent metabolisable energy (AMEn) and digestive organs morphometry in broiler chickens. Broilers were fed with one of the six dietary treatments consisting of two basal diets (based on corn or wheat) each with or without xylanase (from bacterial or fungal origin) supplementation. Compared with corn-based diet, feeding birds with the wheat-based diet improved weight gain and feed intake by 4.71 and 4.81%, respectively, and ileal digestibility of dry matter and crude protein were greater in birds fed wheat-based diets compared with the birds grown on corn-based during Days 1–21 of age (p<.05). Villus length and villus length to crypt depth ratio increased (p < .05) in birds received wheat-based diets compared with those fed on corn-based diets. Gizzard weight was greater in birds fed with corn-based diets on days 21 and 42 of age by 11.5% and 31.8%, respectively, compared with those received wheat-based diets (p < .05). Supplementing diets with fungal xylanase increased liver weight in birds grown on wheat-based diets compared with those grown on control and corn-based diets, respectively, on Days 21 and 42 of age (p < .05). It was concluded that supplementing a corn- or wheat-based diet with a xylanase of bacterial or fungal origin had no effect on productive performance or AMEn of diets in broiler chickens during the starter and growing periods.

Partial Replacement of Dietary Methionine with Betaine and Choline in Heat-Stressed Broiler Chickens

We conducted two trials to evaluate the methionine-sparing effects of choline (Chol) and betaine (Bet), and their effects on growth performance and blood antioxidative potential in heat-stressed broiler chickens fed methionine (Met)-deficient diets. We used 360 1-day-old broiler chicks (Ross 308) in a completely randomized study with 5 replicate pens of 12 birds each. After Day 21, we raised the temperature to 35±3°C using an automated air-forced heater for 12 hours/day from 8 am to 8 pm to expose the birds to heat stress. In Trial 1, the treatments comprised a negative control (control-; 1200 mg/kg Met-deficient), a positive control (control+; recommended level of Met), 280Chol (control- plus 280 mg/kg Chol), 560Chol (control- plus 560 mg/kg Chol), 320Bet (control- plus 320 mg/kg Bet), and 640Bet (control- plus 640 mg/kg Bet); and in Trial 2, the treatments comprised a negative control (control-), a positive control (control+), 140Chol+160Bet (control- plus 140 mg/kg Chol and 160 mg/kg Bet), 280Chol+160Bet (controlplus 280 mg/kg Chol and 160 mg/kg Bet), 140Chol+320Bet (control- plus 140 mg/kg Chol and 320 mg/kg Bet), and 280Chol+320Bet (control- plus 280 mg/kg Chol and 320 mg/kg Bet). Compared with the other treatments, the feed conversion ratio (FCR) was improved in the 280Chol and control+ groups in Trials 1 and 2 (P<0.05). In Trial 2, the cost of meat production for the entire experimental period (1–42 days) was higher in the 140Cho+320Bet-fed birds than in the other birds (P<0.05), except the control- birds. Supplementing diets with 280 mg/kg of Chol significantly reduced the serum concentration of uric acid compared with the control+ group (P<0.05). Our results indicate that the Met requirements of heat-stressed broiler chickens can be reduced by 20% (1200 mg/kg) if the diet is supplemented with 280 mg/kg of Chol.