a.h. samie

This experiment was designed to evaluate the effects of different levels of dietary crude protein and threonine on performance، egg quality and histological structure of jejunum in laying hens. One hundred and eighty 48-week old white leghorn hens (Hy-Line، W-36) were randomly assigned to a 3×3 factorial arrangement of treatments based on a completely randomized design that consisted of 9 dietary treatments with 4 replicates of 12 birds each. Experimental diets were included three levels of crude protein (90، 95 and 100% of Hy-Line W36 recommendations) and three levels of dietary threonine (100، 110 and 120% of Hy-Line W36 specifications). The experimental period lasted for a total of 10 weeks and egg quality and performance parameters of laying hens were assessed two times at the end of 5th and 10th weeks of experiment. At final day of trial، two hens per cage were slaughtered to investigate the influence of dietary treatments on jejunal histological structure. Our results showed that decrease in dietary crude protein percent up to 10% and increase of dietaty threonine percent up to 20% had no significant effect on average daily feed consumption، egg production، egg mass، feed conversion ratio، Haugh unit، yolk index and eggshell thickness and hardness. Nonetheless، feeding low-crude protein diets caused to significant decrease on the average of egg weight (P<0. 05). On the other hand، although dietary crude protein reduction had no remarkable effects on villus height، crypt depth and the ratio of villus height to crypt depth، fortification of low-crude protein diets (90% of recommendations) decreased the relative jejunal goblet cell numbers; however، supplementation of diets with 120% threonine could compensate these alterations. In conclusion، although reduction of dietary crude protein level up to 10% had no adverse impact on performance، egg quality and jejunal histological structure of laying hens، the highest relative goblet cell numbers observed when the birds fed high-threonine diets.

This experiment was conducted to determinate the effects of different levels of Amet protein binder (0, 1.5, 3, 4.5 and 6) in substitution for fish meal on performance and digestibility of nutrients. This study used 400 broiler chickens (Ross strain) with 5 treatments of 4 replications in a completely randomized design. Weight gain, feed consumption, and feed conversion ratio were determined at the end of each phase of the experiment. In addition, the digestibility of nutrients and apparent metabolizable energy (AMEn) of the whole diets were measured by sampling excreta. The results showed that levels of 4.5 and 6% of Amet significantly decreased feed consumption (P< 0.01). Feed consumption was higher for 1.5, 0(control), and 3% Amet in diets, respectively. At the starting phase, 1.5% Amet treatment improved feed conversion ratio (P<0.01). The treatments 6% and 4.5% Amet increased feed conversion ratio in all phases of experiment and the final phase. Percentages of abdominal fat were not significantly affected by treatments. Replacement of different levels of Amet except the treatment 6% had no significant effect on percentage of carcass. The level of 1.5% Amet versus control significantly increased AMEn (P<0.01). It seems that the inclusion of 1.5% Amet binder in the diet can positively affect performance and AMEn of diet in broiler chickens.

In order to assess and determine amino acids profile and their availability in different sorghum grain (SG) varieties, three SG varieties including low tannin (0.09% , LTS), medium tannin (0.19%, MTS) and high tannin (0.37%, HTS) were grown at the same location. The grains were analysed for their proximate analyses, tannin and amino acids. True amino acid availability (TAAA) was obtained by Sibbald’s method using ceacectomized single comb leghorn cockerels. The results showed that methionine and cystine were the first and the second limiting amino acids, respectively in LTS and MTS. But in HTS, lysine (0.166%) was the first and methionine (0.176%) was the second limiting amino acid. Methionine content was 0.114% , 0.182% and 0.176% for LTS, MTS and HTS, respectively. Although, crude protein was lower in HTS (10%) than the other SG, but histidine, methionine and isoleucine were higher for HTS in comparison to LTS and MTS. TAAA decreased when tannin content increased and all amino acids had a lower availability in HTS than LTS and MTS (P<0.05). Methionine in HTS and LTS and glutamic acid in MTS had the highest availability. The availability of proline was most affected by tannin, and its availability was 91.55% for LTS, 84.82% for MTS and 22.82% for HTS (P<0.05).

The effects of dietary vitamins C (VC), E (VE) and sunllower oil (SFO) on immune responses ofheat-stressed male broiler chickens were evaluated. Ali birds were kept under consistent temperatures from 10:00 to 20:00 and from 20:00 to 10:00 throughout the 1-49 day of age period. Antibodies to Newcastle disease virus (NDV) in serum on thelOth day ofpostimmunization at 18, 35 and 48d of age were determined. At 7wk, CD4/CD8 T lymphocyte ratios in peripheral blood were determined. VC, VE, SFO or their interaction had not signilicant effects on immune responses indices and total mortality. However. chicks fed the VE-supplcmentcd diet had a higher antibody titer against NDV at 18 and 48d of age and higher CD4/CD8 lymphocyte ratios. In addition. increasing SPO from 0 to 2.5%, enhanced anti-NDV levels at 18 and 35d of age and increased CD4/CD8 ratios at 49d of age. Moreover, total mortality was decreased with increaseing VC concentration from 0 to 255ppm, VE from 0 to 288ppm and SFO from 0 to 2.5 and 5%. These results suggest that immune responses and especially mortality in hcat-stressed broiler chickens be ameliorated by use of SFO accompanied by dietary VE or VC supplementation.

An experiment was carried out to determine the effects of different levels of lysine and protein on the performance of 240 Hy-Line W36 layers. Ten experimental diets were tested in a 2×5 factorial arrangement with a completely randomized design. Two basal diets (13 and 14% protein) were tested at different levels (10 and 20% lower than NRC, NRC and 10 and 20% above NRC recommendations). Dietary lysine levels were 0.56, 0.62, 0.69, 0.76 and 0.83%. During the three months of experimental period, egg production, egg weight, egg output, feed intake and conversion and lysine and protein intake were determined. The results indicated that 0.76% lysine and more (10 and 20% above NRC recommendation) with 13% dietary protein led to significantly (P<0.05) higher egg production, egg output and better feed conversion, but there was no significant difference regarding egg weight. The difference in performance with different levels of lysine was lower in the 14% dietary protein than that in the 13% one. In the 14% dietary protein, the lowest level (0.56%) of lysine led to significantly (P<0.05) lower egg production and egg output and higher feed conversion. The best performance with the 14% dietary protein belonged to 0.62% dietary lysine (10% below NRC recommendation). The 14% dietary protein had significantly (P<0.05) higher egg production, egg output and feed intake than the 13% dietary protein, regardless of dietary lysine but there was no significant difference regarding egg weight and feed conversion. The best and most economical performance belonged to the 0.76% lysine and 13% protein diet. The results of this experiment indicated that reducing dietary protein and addition of lysine to the diets of post peak laying hens can obtain an equal performance to the higher dietary protein, thus reducing production costs.

The objectives of this study include the determination of the growth potential of Naeini lambs when fed with diets varying in energy and protein concentrations and also an investigation of the influence of level of energy and/or protein intake on carcass characteristics and composition. Ninety Naeini weather lambs (initial live weight 29.89 ± 2.9 kg) were used in a 92-day feeding experiment. Animals were blocked to each of nine dietary treatments. Diets contained either 2, 2.25 or 2.5 Mcal ME/Kg DM and 11.7, 13.2 or 14.7% CP diets were fed in a 3 × 3 factorial arrangement in randomized complete blocks. Lambs fed with high energy diets consumed significantly more feed (P<0.05) than lambs given the medium (ME) or low energy (LE) diets. The average final body weight and daily weight gain for lambs fed with HE, ME and LE diets were 41.4, 38.3, 34.5 Kg and 162, 124, 74 g/d, respectively, which were significantly different (P<0.05). Feed conversion ratio in HE group was significantly lower (8.3) than ME (10.4) or LE (14.3) groups. Energetic efficiencies and protein efficiencies were better for HE than for ME and LE diets. Increasing dietary energy significantly (P<0.05) improved energy and protein efficiencies of the diets. Dressing percentage, lean meat and eye muscle depth were significantly (P<0.05) improved with increasing levels of energy in the diet, but also increased dissectible fat. No significant changes were observed in bone percentage and body ash due to any changes in dietary energy. As the protein level of rations increased, feed conversion ratio and carcass meat percentage increased, but carcass protein percentage decreased.

This experiment was conducted to determine the requirements of vitamin supplement and available phosphorus in broiler chickens from 42 to 56 days of age. In a completely randomized design, with a 3×3×3 factorial arrangement, 270 one-day-old commercial broiler chicks were divided into 27 groups (replicates) with 9 treatments, 3 replicates and 10 chicks in each group. Each of the nine diets was given to each treatment from 42 days of age. Levels of vitamin supplement were 0.5, 0.25, 0% and available phosphorus levels were 0.27, 0.22, 0.16%. Diets were isocaloric and isoprotein. Group weight and feed consumption of each replicate were determined after 42 and 56 days of age and daily gain, daily feed consumption and feed conversion were calculated. Percent of carcass components and tibia ash were determined. Results indicated that removal of vitamin supplement from 42 to 56 days of age did not have any significant effects on daily gain, daily feed consumption, feed conversion, live weight, viscera, abdominal fat, carcass weight, wings, neck and back bone. Also, reduction of available phosphorus did not have any significant effect on daily feed consumption, feed conversion, live weight, viscera, abdominal fat, carcass weight, breast meat, femurs, wings, neck and tibia ash. Interaction between vitamin and phosphorus were significant for daily gain, daily feed consumption, live weight, wings, neck and tibia ash (P<0.005) and were highly significant for breast meat, femurs, and back bone (P<0.00l).

In order to study the effects of Total Dissolved Solids (TDS) in water on the performance of broiler chickens, preliminary data were obtained on water resources of Isfahan Province. Complementary tests and analyses were also performed including physical, chemical and microbial ones. Six different water qualities based on TDS contents of less than 1000, 1000-2000, 2000-3000, 3000-4000, 4000-5000 and more than 5000 ppm were selected. The main experiment lasted for 7 weeks (7-56 days), using 288 chickens in a completely randomized design, with 3 replications, while, the environmental and genetic factors were controlled in an identical broiler housing. The results showed that using water with different TDS contents had the most negative effects on mortality rate (%) in the rearing period and up to 56.2% mortality was recorded at the highest TDS content. Water consumption showed high and positive correlation (P < 0.05) with TDS (r = +0.74). Correlation between TDS and bedding moisture was also high (r = +0.65) and significant (P < 0.05). The differences between final body weight of control chickens and highest level of TDS were significant (P < 0.05). Feed intake also was affected by different TDS contents and showed similar results as with body weight. Increasing the TDS level decreased the abdominal fat in the female chickens and ash content of tibia in the male chickens. It is concluded that water TDS should be considered for the development of broiler chicken farms. Therefore, it is recommended that higher quality waters (with a TDS content of 3000 ppm) must be used for this purpose. Otherwise, appropriate systems should be used to improve physical and chemical composition of the water.