Effect of synbiotic supplementation and dietary fat sources on broiler performance, serum lipids, muscle fatty acid profile and meat quality.

A 42-d trial was conducted to investigate the effect of adding a synbiotic supplement to diets containing two different types of fat on performance, blood lipids and fatty acid (FA) composition and oxidative stability of breast and thigh meat in broilers. A total of 800 one-d-old male broiler chickens were randomly assigned into 1 of 8 treatments with 4 replicates of 25 birds per treatment. The experiment consisted of a 4 × 2 factorial arrangement of treatments including 4 concentrations of synbiotic (0, 0.5, 1 or 1.5 g/kg diet) and 2 types of fat [sunflower oil (SO) or canola oil (CO)] at an inclusion rate of 50 g/kg diet. Dietary fat type did not affect body weight gain (BWG) or feed conversion ratio (FCR) during the overall experimental period (0-42 d). However, fat type modified serum lipid profile and FA composition and 2-thiobarbituric acid-reactive substances (TBARS) content in breast and thigh meat. The addition of synbiotic to the diet linearly improved overall BWG and FCR and also decreased serum cholesterol and low-density lipoprotein cholesterol concentrations. The TBARS value in thigh meat after 30 d of storage at 4°C was linearly decreased as the synbiotic inclusion concentrations in the diets increased. Dietary synbiotic also decreased the proportion of monounsaturated fatty acids and increased n-6 polyunsaturated fatty acid (PUFA) concentration in thigh meat, whereas the FA profile of breast meat was not affected by synbiotic supplementation. Moreover, the PUFA/SFA ratio in the breast meat was linearly increased when synbiotic was included in the CO-containing diets. In conclusion, the addition of synbiotic to broiler diets had a positive effect on growth performance, blood lipid profile and meat quality. The results also support the use of synbiotic to increase the capacity of canola oil for enhancing PUFA/SFA ratio of breast meat in broilers.

The effect of feeding excess arginine on lipogenic gene expression and growth performance in broilers.

1. Reducing excess fat accretion is important for both human health and animal production. The present study was conducted to investigate the effects of arginine (Arg) on the regulation of lipogenic gene expression and on growth performance. 2. One-d-old female broiler chicks (Ross, n = 192) were used in a completely randomised design with 4 dietary treatments in which diets included 100% (CTL), 153% (LArg), 168% (MArg) and 183% (HArg) of the recommended concentration of digestible Arg. 3. Results showed that high concentrations of Arg improved body weight gain, feed efficiency, meat production, fat and crude protein content of breast muscle and plasma thyroid hormones. Conversely, abdominal fat, cholesterol, triglyceride and urea were lower with higher concentrations of Arg. Dietary arginine increased lipogenic gene expression in muscles, while decreasing those in adipose tissue and liver. 4. It was concluded that increasing Arg in the diet reduced abdominal fat content, enhanced intramuscular fat and increased muscle and protein gain. Furthermore, Arg supplementation at the MArg concentration improved growth performance, and at HArg had the greatest effect on fat reduction.

The effect of increasing feeding frequency on performance, plasma hormones and metabolites, and hepatic lipid metabolism of broiler breeder hens.

An experiment was conducted to study the effects of feeding regimens on reproductive performance, plasma hormone and metabolite levels, and hepatic lipid metabolism of Cobb 500 broiler breeder hens from 26 to 38 wk of age. Seventy-two birds were used in a completely randomized design with 3 treatments, each replicated 4 times. Treatments were as follows: 1) once a day feeding, in which birds were fed once a day at 0615 h (control), 2) twice a day feeding, in which daily allocated feed was fed in 2 equal meals at 0615 and 1215 h, and 3) thrice a day feeding in which daily allocated feed was offered in 3 equal meals at 0615, 1215, and 1815 h. Through 38 wk of age, total hen-day egg production in the hens fed twice and thrice a day was greater (67.1 and 67.2 vs. 62.2 eggs/hen, P < 0.01). Similarly, egg weight was higher (P < 0.01) in birds fed more than once a day. Multi-meal-fed birds had significantly lower plasma triiodothyronine and glucose at 32 wk and also lower glucose and cholesterol, and higher 17ß-estradiol levels at 38 wk than those fed once a day (P ≤ 0.05). Hepatic expression of malic enzyme, fatty acid synthase, acetyl-CoA carboxylase, and ATP citrate lyase relative to ß-actin decreased (P < 0.05) in birds fed twice and thrice a day compared with birds fed once a day at peak egg production (32 wk). In contrast, feeding regimens did not affect the hepatic gene expression of lipogenic enzymes after peak egg production at 38 wk. Stearoyl-CoA desaturase 1 (SCD1) gene expression was constant over dietary regimens. There was no difference in malic enzyme activity in multi-meal-fed birds at 38 wk. In summary, feeding broiler breeder hens 2 or 3 meals per day improved the reproductive performance during the early lay cycle. Implementing twice or thrice a day feeding regimens altered hepatic lipogenic gene expression in broiler breeder hens only at peak egg production, which indicated a short-term effect of increasing feeding frequency on hepatic lipid metabolism.

Effects of feeding regimen, fiber inclusion, and crude protein content of the diet on performance and egg quality and hatchability of eggs of broiler breeder hens.

A 12-wk experiment was conducted to study the effects of feeding regimen, inclusion of a fiber source, and CP content of the diet on performance of broiler breeder hens. In total, 360 hens and 60 males, 43 wk of age, were assigned to 60 floor pens (6 hens and 1 male each). There were 12 treatments arranged factorially with 2 feeding regimens [restricted (R) and liberal feeding (close to ad libitum consumption; LIB)], 3 sources of fiber (0, 3% inulin, and 3% cellulose), and 2 levels of CP (14.5 and 17.4%). No interactions among main effects were observed for any of the traits studied, and therefore, only main effects are presented. Body weight, liver weight, and abdominal fat weight were higher (P < 0.001) for the LIB than for the R-fed hens. However, egg production (P < 0.001), fertility index (P < 0.05), and percentage of hatch (P < 0.01) were lower for LIB than for R hens. The weights of ovaries (P < 0.05) and the size of the first preovulatory follicle (P < 0.05) were higher for the LIB than for the R hens. Also, egg yolk, egg weight, and BW of the hatching chicks were higher (P < 0.001) for the LIB hens. The inclusion of a fiber source in the diet decreased (P < 0.05) feed intake, BW gain, absolute liver and abdominal fat weight, and egg yolk weight, with effects being more pronounced (P < 0.05) with cellulose than with inulin. Hens fed additional fiber produced more (P < 0.05) eggs that were more fertile (P < 0.05) than control hens. Crude protein content of the diet did not affect hen performance but reduced (P < 0.01) the relative weight of the liver, ovary, and abdominal fat. It is concluded that the inclusion of inulin or cellulose in the diet improved hen performance and that an increase in dietary CP reduced obesity in broiler breeder hens.

Dietary fibers and crude protein content alleviate hepatic fat deposition and obesity in broiler breeder hens.

The effects of inclusion of cellulose or inulin as a source of dietary fiber and CP content of the diet on hepatic fat deposition were investigated in hens fed restricted or close to ad libitum consumption. There were 12 dietary treatments forming a 2 × 3 × 2 factorial with 2 feeding regimens [restricted and liberal (close to ad libitum consumption; LIB)], 3 fiber sources (control, 3% inulin, and 3% cellulose), and 2 levels of CP (14.5 and 17.4%). Hens were assigned in groups of 6 to 60 floor pens. From 43 to 55 wk of age, hens fed LIB showed increased activity of the hepatic malic enzyme (MalE; P < 0.01), which led to an increase (P < 0.001) in liver weight and hepatic lipid deposition and was associated with enhancements (P < 0.05) in plasma levels of glucose, triglyceride, total cholesterol, and low-density lipoprotein cholesterol. Abdominal fat deposition and BW of the hens increased (P < 0.001) with liberal feeding. Inclusion of inulin in the diet reduced (P < 0.05) liver and abdominal fat weight, whereas cellulose inclusion decreased (P < 0.05) feed intake, abdominal fat, and BW. An increase in CP content of the diet from 14.5 to 17.4% reduced MalE activity (P < 0.001), liver weight (P < 0.001), and the accumulation of lipids and cholesterol in the liver, as well as plasma triglyceride concentration and abdominal fat pad weight (P < 0.05). It is concluded that fiber inclusion reduced abdominal fat and liver weight, with effects being more pronounced with cellulose than with inulin. An increase in dietary CP reduced MalE activity and alleviated hepatic and plasma lipid concentration; therefore, it might be a practical approach to reduce the incidence of obesity-linked problems in broiler breeder hens. The combination of high-CP diets and the inclusion of a fiber source did not suppress liver lipid content over that observed with the high-CP diet, exclusively.

Effects of diet acidification and xylanase supplementation on performance, nutrient digestibility, duodenal histology and gut microflora of broilers fed wheat based diet.

1. The objective of this experiment was to study the influences of xylanase and citric acid on the performance, nutrient digestibility, digesta viscosity, duodenal histology, and gut microflora of broilers fed on a wheat based diet. 2. The experiment was carried out as a 2 × 3 factorial arrangement with two concentrations of xylanase (0 and 200 mg/kg) and three concentrations of citric acid (0, 20 and 40 g/kg). A total of 408 one-day-old chickens with similar body weight were distributed into 24 pens with 17 birds/pen. Each dietary treatment was given to 4 replicate pens from 0 to 24 d of age. To determine the apparent nutrient digestibility, chromic oxide (3 g/kg) was added to the diets as an indigestible marker. 3. Xylanase significantly increased body weight gain at 24 d of age by 1·4% and improved gain-to-feed (G:F) by 3·6%. The inclusion of 40 g/kg citric acid decreased feed intake and body weight gain by 15·4% and 11·8%, respectively. The inclusion of 20 g/kg of citric acid decreased feed intake, but it did not affect body weight gain of broilers at 24 d of age. The inclusion of 20 and 40 g/kg citric acid improved G:F by 3·8 and 4·3% respectively. Xylanase significantly decreased the viscosity of digesta and improved retention of DM, CP, and energy. 4. Xylanase and citric acid did not have any effect on the histo-morphology of the duodenum and intestinal microbial population. 5. In conclusion, citric acid at 20 g/kg decreased feed intake, did not have a negative effect on body weight gain, and improved G:F. Xylanase decreased digesta viscosity, increased nutrient retention and consequently improved performance of broilers fed on a wheat based diet.

Effects of wheat inclusion and xylanase supplementation of the diet on productive performance, nutrient retention, and endogenous intestinal enzyme activity of laying hens.

An experiment was conducted to study the effects of inclusion of a wheat cultivar (high in nonstarch polysaccharides) and xylanase supplementation of the diet on productive performance, pH of the gastrointestinal tract, nutrient retention, and intestinal enzyme activity of Hy-Line W-36 laying hens from 25 to 47 wk of age. The experiment was completely randomized with 8 treatments arranged factorially with 4 levels of wheat (0, 23, 46, and 69%) that corresponded to a dietary arabinoxylan content of 3.0, 3.3, 3.6, and 3.9%, with or without xylanase supplementation. Each treatment was replicated 5 times. For the entire experimental period, egg weight (P < 0.05) and egg mass (P < 0.01) were reduced and the feed conversion ratio was hindered (P < 0.05) with increased levels of wheat in the diet, but ADFI and egg production were not affected. Xylanase supplementation improved egg production (P < 0.05), egg mass (P < 0.01), and the feed conversion ratio (P < 0.01). Diet did not affect egg quality at any age, except for shell thickness at 47 wk that was improved with xylanase supplementation (P < 0.05). Digesta pH of the different organs of the gastrointestinal tract was not affected by wheat inclusion or xylanase supplementation. Ileal viscosity increased (P < 0.001) with wheat inclusion and decreased (P < 0.001) with xylanase supplementation at all ages. Fat digestibility (P < 0.001) decreased with increased levels of wheat but AME(n) content of the diets (P < 0.05) and nitrogen retention were not affected. Wheat inclusion increased (P < 0.001) amylase (33 wk), lipase (33 wk), and aminopeptidase (47 wk) activity in the duodenum as well as lipase activity in the jejunum at 47 wk of age. However, xylanase supplementation did not affect the activity of any of the enzymes studied. It is concluded that most of the negative effects of wheat inclusion in the diet were reduced or even disappeared with xylanase supplementation. Wheat with a high nonstarch polysaccharide content (Pishtaz cultivar) can be used at levels of up to 69% in laying-hen diets without negatively affecting bird performance, provided that feeds are supplemented with xylanase.

Comparison of marine algae (Spirulina platensis) and synthetic pigment in enhancing egg yolk colour of laying hens.

The objective of this experiment was to determine the effects of dietary marine algae (Spirulina platensis) on egg yolk colour, and compare the effectiveness of Spirulina and synthetic pigment in enhancing egg yolk colour of laying hens fed on a wheat-based diet. In total, 160 Hy-line W36 laying hens of 63 weeks of age were studied by dividing them into 5 groups, 32 birds in each. Except for the control group (based on wheat and soyabean meal), the feed for three other groups contained 1·5, 2·0 and 2·5% of Spirulina; while one group contained synthetic pigments (BASF Lucantin® yellow: 30 mg/kg, and BASF Lucantin® red: 35 mg/kg). Egg production, feed intake, feed conversion ratio (FCR), egg weight and egg yolk colour were determined. A significant increase in egg yolk colour was observed in the treatments that received the Spirulina and synthetic pigment, compared with the control diet. There were no significant differences between the treatments with 2·5% Spirulina and synthetic pigment in enhancing egg yolk colour. Finally, the results indicated that the diet containing 2·5% Spirulina could be as effective as the diet with synthetic pigment in producing an agreeable egg yolk colour.

Effects of xylanase and citric acid on the performance, nutrient retention, and characteristics of gastrointestinal tract of broilers fed low-phosphorus wheat-based diets.

An experiment was conducted to study the effects of xylanase and citric acid on the performance, nutrient retention, jejunal viscosity, and size and pH of the gastrointestinal tract of broilers fed a low-P wheat-based diet. The experiment was conducted as a 2 × 3 factorial arrangement with 2 levels of xylanase (0 and 200 mg/kg) and 3 levels of citric acid (0, 20, and 40 g/kg). Each of the 6 dietary treatments was fed to 4 replicate pens (17 birds/pen) from 0 to 24 d of age. Chromium oxide (3 g/kg) was added to the diets as an indigestible marker to determine the apparent nutrient retention. No interaction effect was observed between xylanase and citric acid in any measured response. Xylanase did not affect feed intake but significantly increased BW gain by 3.6% (P < 0.05) from 1 to 24 d of age and improved G:F by 3.9% (P < 0.01). The inclusion of 40 g/kg of citric acid decreased (P < 0.01) BW gain and feed intake by 8.6 and 12.5%, respectively. The inclusion of 20 and 40 g/kg of citric acid improved G:F by 2.3 and 4.5% (P < 0.05), respectively. Xylanase significantly decreased the viscosity of digesta and improved the retention of DM, CP, and energy, but did not have a significant effect on the retention of fat and P. Inclusion of 20 and 40 g/kg of citric acid in the diets increased P retention by 15.8 and 16.3% (P < 0.01), respectively. Citric acid significantly decreased the pH of crop contents (P < 0.05). In conclusion, citric acid, at the 40 g/kg inclusion level, reduced feed intake and BW gain but improved G:F and P retention. Xylanase decreased digesta viscosity, increased nutrient retention, and consequently improved the performance of broilers fed the low-P wheat-based diet. Thus, adding 20 g/kg of citric acid, especially in the starter period, and 200 mg/kg of xylanase to low-P wheat-based diets can be helpful.

Efficacy of combined or single use of Lactobacillus crispatus LT116 and L. johnsonii LT171 on broiler performance.

1. The objective of this research was to investigate the efficacy of combined or single use of Lactobacillus crispatus LT116 and Lactobacillus johnsonii LT171 on broiler performance. 2. A total of 320 one-d-old male Ross broiler chicks were allocated in 4 experimental treatments for 6 weeks. The experimental treatments received a maize-soybean meal basal diet that was supplemented as follows: 'control', with no other additions; 'LJ', 1 × 10(6) CFU of L. johnsonii LT171; 'LC', 1 × 10(6) CFU of L. crispatus LT116; and 'LCJ', 0·5 × 10(6) CFU of L. johnsonii LT171 + 0·5 × 10(6) CFU of L. crispatus LT116/g of the diet. A suspension of sheep red blood cells (SRBC) was injected into the breast of 8 birds from each treatment on d 14 and 30, and the antibody titre was measured on d 20, 26, 36 and 42. 3. Body weight was improved when compared with control for broilers fed diets supplemented with LCJ. The feed conversion ratio (FCR) decreased in LC and LCJ groups compared with control. The number of coliforms in the ileum of LJ, LC and LCJ birds was lower than that from the control birds. However, only the LCJ treatment significantly decreased the number of coliforms in the caecum. The LCJ group had greater villus height in the duodenum than the LC group, and both LCJ and LC groups showed increased villus height in the duodenum and jejunum relative to the control. Antibody titre against SRBC was higher for the LCJ group than for the LJ and control groups in terms of secondary immune response (mean of 36 and 42 d). 4. This study showed, compared with the control, that the combination of Lactobacillus spp. could positively affect body weight, coliform numbers in the caecum and immune response.

A twice-a-day feeding regimen optimizes performance in broiler breeder hens.

To evaluate the effects of different methods of feed allocation on performance, plasma hormone concentration, and ovarian morphology, an experiment was conducted using 32 Cobb 500 broiler breeder hens. The experiment was started at 27 wk and lasted to 39 wk of age. Feeding regimens included: i) hens with an ad libitum feeding program, ii) hens that received their restricted feed once a day, iii) hens that received their restricted feed twice a day, and iv) hens that received their restricted feed 3 times a day. Each hen was assumed as an experimental unit and treatments were replicated 8 times. Daily egg production, BW, and egg and yolk weights were measured. Two blood samples were taken 3 and 6 h after the first feed allocation every 2 wk. Plasma samples were assayed for glucose, triacylglycerol (TAG), cholesterol, as well as leptin-like concentration, glucagon, triiodothyronine, thyroxine, progesterone, estradiol, and testosterone. Liver, abdominal fat pad, and ovary were collected at necropsy. Ovaries were weighed and follicles were characterized as large yellow follicles, small yellow follicles, and large white follicles. Results showed inferior egg production in ad libitum-fed birds along with high levels of plasma glucose, TAG, cholesterol, leptin-like concentration, and testosterone. Twice-a-day-fed birds produced more egg in the entire production period than once-a-day-fed birds. Better performance of twice-a-day-fed hens was associated with lower plasma glucose, TAG, and leptin-like concentration, whereas their estradiol and glucagon were higher than once-a-day-fed hens. Results obtained in our study suggest that allocation of restricted feed 2 times a day may alleviate or delay lipotoxicity development and improve reproductive performance in broiler breeder hens.

Impact of dietary crude protein and amino acids status on performance and some excreta characteristics of broiler chicks during 10-28 days of age.

A study was conducted in a completely randomised design to evaluate the effects of providing almost all important essential amino acids (EAA) in low-crude protein (CP) diets equal to that of higher CP diets in broiler chickens. Also the effects of additional mixture of glycine (Gly) and glutamic acid (Glu) or supplementation of excess EAA to low-CP diets on the live performance and excreta characteristics including pH, moisture, nitrogen, uric acid and ammonia concentration were measured to ascertain the optimum CP concentration for the maximum performance and reduced excreta ammonia concentration. Male, broiler chickens growing from 10 to 28 days of age were fed eight experimental diets. Reducing dietary CP below 19% negatively affected performance. Adding the Gly and Glu mixtures to 17% CP diets improved live performance. Reducing CP to 19% with a normal amino acids status declined N, ammonia, uric acid, moisture and pH of excreta significantly. These findings suggest that diminishing dietary CP from 23% to 19% while maintaining adequate EAA levels during 10-28 days of age results in not only a significant decline in N emission, but also a probable reduction in the NH(3) volatilisation because of reduction in pH and moisture. Contrary to expectations, reduction of dietary CP below the minimum level (19%) resulted in more ammonia. All these factors may improve on litter and air quality within the housing facility and reduce the ventilation rate required to emit the elevated ammonia gas concentrations.

Effects of reduced calcium and phosphorous diets supplemented with phytase on laying performance of hens.

The aim of this experiment was to examine the potential for reduced environmental impact by reducing dietary calcium and phosphorus content and phytase addition of laying hen diets. A randomized complete block design with a 2x2x2 factorial arrangement of 8 dietary treatments: 2 levels ofphytase (0 and 300 FTU kg(-1)) and 2 mineral levels (Ca: 34/18 and NPP: 3.2/2.2 g kg(-1), respectively). A total of 240 White Leghorn (WL) layers, 25 weeks of age were used. Considering birds in 12 cages as a replicate, 5 such replicates were randomly allotted to each dietary treatment. Individual body weight of the bird was recorded at the beginning and end of the experiment. Egg production on an individual basis was recorded daily and percentage hen day egg production was calculated. The cleaned eggshells were dried for 24 h, weighed and expressed as percentage of whole egg. One bird from each experimental unit were selected at random and killed by cervical dislocation at the end of the experiment and the left tibia was removed. Dried bone samples were ashed at 680 degrees C for 12 h for estimation of bone ash. The results of this experiment showed that reducing Ca and NPP (Non-Phytate Phosphorus) without phytase decreased BWG (Body Weight Gain), feed intake, FCE (Feed Conversion Efficiency), egg production, egg shell weight and tibia ash. However, phytase addition to low mineral diets completely corrected the adverse effects associated with low dietary Ca and NPP. It can therefore be concluded that reducing levels of Ca and NPP below current standards and phytase supplementation can reduce pollution potential from laying hen production without adversely affecting bird performance or welfare.

Screening of lactic acid bacteria toward their selection as a source of chicken probiotic.

In this study, 332 lactic acid bacteria of broiler gut origin were investigated as putative probiotic candidates. Sixty-two bacteria showed the highest aggregation while showing antibacterial effects against Salmonella Enteritidis, Salmonella Typhimurium, and Escherichia coli O78:K80. Enzymatic activities of the selected bacteria were examined. No lipase activity was detected, but all of them showed almost similar proteolytic activities. However, they had different amylase and phytase activities. Four of the 62 bacterial strains were selected as a result of aggregation and amylase tests. They were chosen for the following attributes: high cell surface hydrophobicity, co-aggregation, and resistance to bile salts and also acidic conditions. Finally, Lactobacillus crispatus was selected as a source of potential probiotic because of its predominant characteristics in comparison to the other isolated strains from the gastrointestinal tract of chickens. This study has provided a good arrangement of rapid methods for screening a high number of bacteria: a series of beneficial tests that are used together for the first time on chickens, and not any other animals.

Effects of fortifying low crude protein diet with crystalline amino acids on performance, blood ammonia level, and excreta characteristics of broiler chicks.

A study was conducted in a completely randomized design to evaluate the performance, excreta characteristics, and some blood nitrogen metabolite concentrations of 28-d-old male broilers fed 4 experimental diets in which CP was decreased in a stepwise manner from 23 to 17%. The other 4 diets were formulated to have 19 and 17% CP, in which 2 of them contained an additional 10% of particular essential amino acids (EAA) and 2 were supplemented with Gly and Glu. Ileal digestible quantities of all EAA were almost equal in the diets, and total amount of each EAA was maintained at or above NRC requirements. Decreasing dietary CP below 19% depressed performance and appetite and increased fat deposition in the whole body and abdominal cavity significantly. Adding the Gly and Glu mixtures to low-CP diets improved performance and decreased fat deposition. Uric acid, moisture, and acidity of excreta were decreased by reduction of dietary CP; excretory ammonia level was increased in 17% CP diets. Blood ammonia level was increased and plasma uric acid was decreased with reduction of CP to 17%. Supplementing Gly and Glu increased plasma and excretory uric acid level in spite of decreasing blood ammonia concentration. The aminostatic hypothesis cannot explain the sharp reduction in appetite in this experiment, because alteration of dietary CP had no significant influence on most plasma free amino acid levels. Therefore, reduction of CP to 19% not only does not impair performance but also decrease nitrogen, ammonia, and pH of excreta that may improve upon litter and air quality. Adding large amounts of crystalline EAA to diets with low intact CP increased blood and excretory ammonia concentration, which due to its negative effects on tissue metabolism may be the main cause of retarded growth and appetite in decreased CP diets below 19%.

Determination of the best level of dietary energy with two diet formulation methods based on total and digestible amino acid on broiler diet.

In order to evaluate the effects of different levels of energy and methods of formulation of Amino Acid (AA) requirements of diets, this experiment was conducted using 392 broiler chicks. The experiment was carried out using a complete randomize block design with 7 levels of energy 3175, 3075, 2975, 2875, 2775, 2675 and 2575 kcal kg(-1) for grower diet and 3225, 3125, 3025, 2925, 2825, 2725 and 2625 kcal kg(-1) for finisher diet and two methods of formulation of diets AA requirements (total and digestible) as a factorial arrangement. Results showed that by increasing level of energy feed intake, body weight and FCR were promoted in grower diet (p<0.05). Effect of decreasing level of energy up to 2725 and 2825 kcal kg(-1) was not significant on body weight and FCR in finisher diet, respectively. Formulating of diet based on total or digestible AA affected feed intake and FCR in finisher diet (p<0.05). Interaction effect of independent factors affected on body weight in grower diet (p<0.05). Decreasing level of energy increased gastrointestinal tract percentage weight (p<0.05). Formulation of diet based on digestible AA decreased gastrointestinal tract percentage weight (p<0.05). Abdominal fat decreased significantly as ME content of diets decreased. Results showed that it's possible to reduce the level of energy up to 3175 kcal kg(-1) in grower and 2725 kcal kg(-1) in finisher diet for giving the best and economical performance response. Formulation of diet based on digestible AA in finisher diet resulted in promotion of performance.

Comparison of four induced molting methods based on subsequent performance and welfare of Single Comb White Leghorn hens.

A total of 400 Single Comb White Leghorn hens at 80 weeks of age were used in present study. Four treatment groups that were consisted of six replications with 10 hens per each replication were considered. In the first treatment, food and water were removed for the first 2, 4, 6 and 8 days. However, on days 3, 5, 7, 9 and on day 10 until day 28 hens were fed 45 g of food per hen (ON-OFF group). In the second and third groups, food was withdrawn for 10, 14 days, respectively and oyster shell and water were provided for ad libitum until day 28 (California and North Carolina treatments (CAL, NC groups)). The last group (full-food treatments (FF group)) was the hens that were non-food-deprived and were fed corn molt diet for 28 days ad libitum. In all treatment groups at day 29, hens were returned to a full food layer ration and received 16 h of light day(-1). Body weight, egg production, egg weight, relative eggshell weight, internal egg quality, egg specific gravity and mortality were determined. Differential leukocyte count and antibody response were also measured. The results demonstrated that induced molting increased egg production according to pre-molt egg production. There was not a significant difference in the rate of egg production during the peak period of post molt production for treatments. No significant differences were detected in differential leukocyte counts and antibody response against Sheep Red Blood Cell (SRBC) between treatments at pre molt and post molt of the experiment. This study indicated that diets with high corn level (FF groups) are effective and simplified nonfood removal procedure for welfare molting hens.

Effects of ethylenediaminetetraacetic acid on phytate phosphorus utilization and efficiency of microbial phytase in broiler chicks.

Previous studies have suggested that organic acids may improve P utilization in animals. To evaluate the ability of ethylenediaminetetraacetic acid (EDTA) to improve phytate P utilization and the possible synergistic effect between EDTA and microbial phytase (MP) an experiment was conducted using 360 Ross 308 broiler chicks. The experiment was carried out using a completely randomized design with a 3*2 factorial arrangement (0, 0.1 and 0.2% EDTA and 0 and 500 IU MP). Four replicate of 15 chicks per each were fed dietary treatments including (i) P-deficient basal diet [0.2% available phosphorus (aP)] (NC); (ii) NC + 500 IU MP per kilogram of diet; (iii) NC + 0.1% EDTA per kilogram of diet; (iv) NC + 0.1% EDTA and 500 IU MP per kilogram of diet; (v) NC + 0.2% EDTA per kilogram; and (vi) NC + 0.2% EDTA + 500 IU MP per kilogram of diet. Weight gain (WG), feed efficiency and serum Ca, P and alkaline phosphatase (ALP) were assessed. Addition of 0.2% EDTA to low aP diets resulted in significantly lower feed consumption (FC) and WG, but 0.1% EDTA did not depress WG compared to NC. Phytase supplementation of P-deficient diets significantly improved WG and feed efficiency, but it had no effect on FC. Microbial phytase supplementation significantly decreased ALP concentration. Results obtained in our study suggest no synergistic effect between phytase and EDTA in broiler chicks.

Effects of glucose injection and feeding oasis on broiler chick's subsequent performance.

An experiment was conducted to investigate the effects of glucose injection and feeding Oasis immediately posthatch on the subsequent performance of broilers. Experiment was carried out using a completely randomized design with factorial arrangement (2 x 2 x 2 x 2). Factors were included egg weight (small eggs weighting between 50 to 60 g and medium eggs weighting between 61 to 70 g), glucose injection (Control with no injection and 0.3 mL glucose injection), feeding in transportation boxes during shipping period (chicks fed Oasis and those hold with no access to feed and water) and house arrival feeding (chicks that receive feed immediately at arrival and those hold for an additional 12 h without feed). Treatments were replicated three times with 25 chicks per each. Live weight and feed intake were measured for each experimental unit at 7, 21 and 42 days of age and then weight gain and feed: gain was calculated. On days 3, 21 and 42, two chicks from each replicate were killed for carcass analysis including yolk sac residue weight (third day), duodenum, jejunum and ileum weight and length and also liver and gizzard weight. Results show an improved Weight Gain (WG) and feed efficiency (p < 0.05) in chicks from medium eggs compared to those from small eggs. A significant interaction (p < 0.05) between glucose injection and egg weight was observed, so that chicks of small eggs with glucose injection show a significant (p < 0.05) depression in WG. Chicks with immediate access to Oasis had greater (p < 0.05) duodenum and jejunum relative weight on day 3 and duodenum on day 42. Oasis fed chicks also had better WG and breast meat yield (p < 0.05) while feeding Oasis did not influence feed efficiency. Feeding Oasis also increased yolk utilization. Chicks with delayed access to feed in the house compensate their initial decreased WG during the later stages. Glucose injection had no beneficial effect, but immediate access to feed in posthatch chicks improved their performance.

Effect of energy levels of diets formulated on total and digestible amino acid basis on performance of female broiler.

In order to evaluate the effects of different levels of energy and method for formulation of Amino Acid (AA) requirements of diets, this experiment was conducted using 294 female broiler chicks. The experiment was carried out using a complete block design with a 7x2 factorial arrangement. Factors were included different levels of energy (7 energy levels) and formulation methods of diets AA requirements (total and digestible). Results showed that feed consumption decreased by increasing level of energy. Body weight and feed conversion ratio were promoted by increasing level of energy. Formulation methods of AA requirement had significant effect on cumulative feed consumption, weight gain (in grower period) and feed conversion ratio (p < 0.05). Interaction effects of independent factors affected on cumulative feed consumption, body weight and feed conversion ratio (p < 0.05). Abdominal fat pad were significantly lower in chicks fed diets formulated on digestible AA basis. Energy content of diets affected fat pad significantly. Abdominal fat pad increased significantly as ME content of diets increased. Results showed that formulation of diet on digestible AA contained the low energy resulted in promotion of performance.