Independent and combined effects of Satureja khuzistanica essential oils and acetic acid on prevalence and intensity of fatty liver syndrome in broiler chickens.

Two hundred fifty two male Ross 308 broiler chicks were raised to examine the effects of Satureja khuzistanica essential oils (SkEO; 0, 200, 300, 400, 500 and 600 mg/bird/day) administrated via oral gavage and dietary supplementation of acetic acid (AA; 0 or 20 g/kg) in a 6 × 2 factorial fashion using a complete randomized block design with seven replicates of three birds each. In Day 34 of age, liver fat percentage decreased by increasing SkEO levels in a quadratic trend (p < .05). Oral gavag of 200 and 300 mg of SkEO decreased AST activity by 16.67% and 16.94%, respectively, compared with the control birds (p < .05). In Day 38 of age, liver percentage was greater by 0.37% in the birds received 400 mg SkEO than those given 500 mg (p < .05). Liver fat percentage decreased in the birds fed the acidified diet and received 300 and 500 mg SkEO as well as in the birds offered 200 and 400 mg of SkEO and fed non-acidified diet than those received acidified diet with no SkEO administration (p < .05). Prevalence of score zero for hepatocytic vacuolations and necrosis was 80.00% and 42.42% in the birds receiving 600 mg SkEO respectively. Median for relative frequency of scores for hepatocytic vacuolations and hepatocytic necrosis was lesser in the birds received SkEO by oral gavage compared with that of control birds (p < .05). In conclusion, administration of SkEO via oral gavage reduced liver fat in broiler chicken but no consistent dosage could be verified as the effective dosage for all ages concerned. The acidified diet per se showed no evident effect on liver fat at all ages considered. The SkEO × AA interaction exhibited promising but unreliable effects on liver colour score in market age (42 days).

Energy utilisation of broiler chickens in response to guanidinoacetic acid supplementation in diets with various energy contents.

This experiment was conducted to investigate the effects of guanidinoacetic acid (GAA) on productive performance, intestinal morphometric features, blood parameters and energy utilisation in broiler chickens. A total of 390 male broiler chicks (Ross 308) were assigned to six dietary treatments based on a factorial arrangement (2×3) across 1-15 and 15-35-d periods. Experimental treatments consisted of two basal diets with standard (STD; starter: 12·56 MJ/kg and grower: 12·97 MJ/kg) and reduction (LME; starter: 11·93 MJ/kg and grower: 12·33 MJ/kg) of apparent metabolisable energy (AME) requirement of broiler chickens each supplemented with 0, 0·6 and 1·2 g/kg GAA. Supplemental 1·2 g/kg GAA decreased the negative effects of feed energy reduction on weight gain across starter, growing and the entire production phases (P<0·05). Energy retention as fat and total energy retention were increased when birds received LME diets supplemented with 1·2 g/kg GAA (P<0·05). Net energy for production (NEp) and total heat production increased in birds fed LME diets containing 1·2 g/kg GAA (P<0·05). A significant correlation was observed between dietary NEp and weight gain of broilers (r 0·493; P=0·0055), whereas this relationship was not seen with AME. Jejunal villus height and crypt depth were lower in birds fed LME diets (P<0·05). Serum concentration of creatinine increased in broilers fed LME diets either supplemented with 1·2 g/kg GAA or without GAA supplementation (P<0·05). Supplemental GAA improved performance of chickens fed LME diet possibly through enhanced dietary NEp. The NEp could be preferred over the AME to assess response of broiler chickens to dietary GAA supplementation.

Effects of feed form and xylanase supplementation on metabolizable energy partitioning in broiler chicken fed wheat-based diets.

An experiment was conducted to investigate the effects of feed form and xylanase supplementation on the growth performance, energetic efficiencies, energy partitioning, and nitrogen (N) balance of Ross 308 male broilers fed wheat-based diets. The experiment was conducted as a 2 × 2 × 5 factorial arrangement with 2 levels of feed forms (mash or pellets) and xylanase (0 or 500 mg/kg), and five feeding levels (ad libitum, 85%, 70%, 55%, and 40% of ad libitum intake). Each of the 20 dietary treatments was fed to 5 replicate pens (5 birds/pen) from 22 to 42 days of age. A significant interaction between feed form and xylanase on was observed for average daily feed intake and heat production (p < 0.01). Pelleting and dietary supplementation with xylanase increased average daily gain and feed conversion ratio but decreased (p < 0.05) average daily feed intake. Broilers fed xylanase-supplemented diet ingested and pelleted diet retained more than in those fed the mash form or the diet without xylanase. Xylanase and pellets decreased (p < 0.01) heat production and metabolizable energy intake (MEI), but increased retained energy (p < 0.05). The birds fed xylanase also needed less MEI per gram of N retained than those fed the diets without enzyme (p < 0.01). Estimation of both metabolizable and net energy requirements for maintenance as a function of BW0.75 showed that requirements for broilers fed pelleted diet and xylanase-supplemented diet were lower than in those fed mash form or the diet without xylanase (p < 0.01). The higher energetic efficiencies for retention were estimated in the birds offered pelleted and xylanase-supplemented diets compared with the values determined for those fed the diet with mash form or the diet without xylanase (p < 0.05). The efficiency of energy utilization for protein for birds fed xylanase-supplemented diets was higher (p < 0.01) than those fed diets without xylanase, and fat deposition for broilers fed the pelleted diet was greater than those fed the mash diet (p < 0.01). Because MEI for maintenance requirements represents a large portion of the MEI, the results from this experiment could be considered in calculation of energy requirements for finishing broilers fed wheat-based diets.

Effects of early growth rate and fat soluble vitamins on glucose tolerance, feed transit time, certain liver and pancreas-related parameters, and their share in intra-flock variation in performance indices in broiler chicken.

Three hundred fifty 18-day-old Ross 308 male chicks were used to examine the effects of early growth rate (x̄-3SD, x̄-2SD, x̄-SD, x̄, x̄+SD, x̄+2SD and x̄+3SD) and a fat soluble vitamin (FSV) cocktail on glucose tolerance, whole tract feed transit time (FFT), certain liver, and pancreas related traits as well as their share in intra-flock variance of body weight (BW) at d 42 and feed intake (FI) and feed conversion ratio (FCR) in d 21 to 42 of age. Birds with a greater initial BW (21 d) showed greater FI during d 21 to 42 of age and gained a higher final BW at d 42 of age. The broilers injected with a FSV cocktail consumed more feed with an improved FCR and achieved a noticeable greater BW at d 42 of age compared with the untreated birds (P < 0.05). Blood glucose at 15 min after oral gavageing of a glucose solution was elevated in all birds faster than those with a body weight close to the mean population BW. Lipase activity increased by 9.75% and amylase activity decreased by 14.9% in the birds treated with FSV injections compared with those received no vitamin. Multivariate step-wise regression analysis showed liver percentage as the leading variable accounting for about 75 and 62.77% of BW and FI variance, respectively. Serum cholesterol concentration was the major predictor in a poor model (R2 = 52.07) generated for FCR, explaining 29.3 of the FCR viability (P < 0.150). It was concluded that the slow and fast growing birds within a flock showed the same efficiency in dietary glucose absorbing and blood glucose clearing. The faster-growing birds demonstrated slower FTT. Liver percentage was the major parameter explaining a significant fraction of the intra-flock variance in BW at marketing age and FI during days 21 to 42 d.

Independent and combined effects of Satureja khuzistanica essential oils and dietary acetic acid on fatty acid profile in thigh meat in male broiler chicken.

A 2 × 6 factorial experiment was conducted to evaluate the effect of Satureja khuzistanica essential oils (SkEO; 0, 200, 300, 400, 500, and 600 mg/bird/day) administered via oral gavage and dietary acetic acid (AA; 0 and 20 g/1 kg) on fatty acids (FA) composition in thigh meat of Ross 308 broiler chickens at days 34, 38, and 42 of age. Dietary AA reduced DWG, DFI, and European economic efficiency index, and increased FCR compared with the nonacidified diet. In day 34 of age, saturated FA (SFA) percentage reduced and polyunsaturated FA (PUFA), n-3, and n-6 percentages increased in the birds that received 400 mg SkEO. Mean monounsaturated FA (MUFA) percentage was greater, whereas PUFA, n-3, n-6, and total FA (TFA) percentages were lesser in the birds fed on the acidified diet. In day 38 of age, mean PUFA, TFA, n-3, and n-6 percentages were greater while MUFA and cis FA (CFA) concentrations were lesser in the thigh muscle of the birds that received 400 mg SkEO. Mean MUFA, PUFA, n-3, n-6, CFA, and TFA percentages were lower in the birds maintained on the acidified diet. In day 42 of age, mean SFA percentage reduced in the birds given 300 mg SkEO, while TFA percentage lowered in the birds that received 200 and 600 mg SkEO. The acidified diet decreased MUFA, TFA, and CFA percentage and increased SFA and the n-6 to n-3 fatty acids ratio of thigh meat in chicken. The results led to the conclusion that the daily enteral administration of SkEO through oral gavage may feasibly modify the fatty acids profile of thigh meat in favor of increased PUFA. Dietary AA and its interaction with SkEO inconsistently modified concentration of certain classes of fatty acids in broiler thigh meat, particularly in advanced ages. Almost all alterations induced by AA-involving treatments in fatty acids composition of thigh meat were on the contrary to the SkEO influences as they were in favor of an increased SFA proportion.

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.