مجله علوم دامی ایران
سال چهلم شماره 3 (پاییز 1388)

The effect of feeding barley-based diets (%60) supplemented with four commercial enzymes containing xylanase and? -glucanase activities were investigated on performance and gastrointestinal size of broiler chicks. The enzyme supplemented diets were compared with unsupplemented barley- or corn-based diets. A total of 234-day-old male broiler chicks (Ross 308) were allocated to 6 treatment groups, with 3 replicates per each treatment group, 13 birds per replicate pen, and the data analyzed in a randomized complete block design. All the enzymes in supplementation with the barley-based diet significantly (P<0.05) increased Average Daily Feed Intake (ADFI) of birds in the grower period, while in the entire period, only enzyme C was significantly (P<0.05) effective on ADFI. Addition of all enzymes to the barley-based diet significantly (P<0.05) improved Body Weight Gain (BWG) and Feed Conversion Ratio (FCR) of broilers in comparison with feeding unsupplemented barley diet in starter, grower as well as in the total period. In contrast, no significant effect was observed in finisher period by enzyme supplementation (P>0.05). As well, in case of the mentioned parameters, no significant differences were observed among any of the enzymes in any period. At 42 days of age, relative weight of pancreas significantly (P<0.05) decreased only by enzymes A, C, and D, but the relative weight of liver and gizzard was not significantly (P>0.05) affected by enzyme supplementation. However, almost all the enzymes employed in the experiments significantly (P<0.05) decreased the relative weight and length of different parts of intestine. The results of the current study show that, addition of all four different enzymes are effective in overcome anti-nutritiving the effect of NSP on broiler performance

The present study was carried out to investigate the replacement of soybean meal by different levels of canola meal (either with or without canola meal undergoing heat processing). Two hundred forty commercial layer hens (LSL strain) at 54th week of age, selected based on the same egg production percentage and body weight. The experimental design was a CRD, in a factorial arrangement of 4 replicates. The factors included were 3 levels of canola meal replacements (33, 66 and 100%) and 3 types of canola meal namely: 1. without processing; 2. dry heat processing (80°C for 30min); 3. autoclaving (120°C with 15lb pressure per inch for 30min). A control diet based on corn and soybean meal was included. The experiment was carried out for three 58 days periods. Feed intake, egg production percentage, egg weight, egg mass, feed conversion ratio, Haugh Unit, yolk color, egg specific gravity, shell percentage, shell thickness, pancreas and liver relative weight, body weight gain, T3 and T4 hormones as well as alkaline phosphatas concentration of plasma were recorded. The results indicated that feed intake, egg weight, egg mass, FCR, Haugh Unit, egg specific gravidity, shell thickness, T3 and T4 hormones and alkaline phosphatase concentration, werent affected by either canola meal and heat processing or the interaction between canola meal and heat processing. Egg production percentage, pancreas relative weight and yolk color were affected by different levels of canola meal (P<0.05). Liver relative weight was affected by heat processing of canola meal (P<0.05). Eggshell percentage was affected by heat processing and as well as canola meal interaction (P<0.01).

Quality of protein fractions, according to Cornell Net Carbohydrate and Protein System (CNCPS), and digestibility coefficients, using Tilley and Terry procedure, of the fresh and ensiled amaranth (Amaranthus hypochondriacus) forage were assessed. The concentration of Crude Protein (CP) and True Protein (TP) in the fresh forage, were respectively 116 and 70 g/kg of DM. Soluble Protein (SP) and A, B1, B2, B3 and C fractions were 411, 395, 16, 349, 158, and 82 g/kg of CP, respectively. Dry Matter Digestibility (DMD), Organic Matter Digestibility (OMD) and Organic Matter Digestible in Dry Matter (OMDDM) of fresh amaranth were respectively 712, 677, and 586 g/kg, and as well Metabolisable Energy (ME) was 9.2 MJ/kg of DM. Ensiling process resulted in increase in CP, SP, and A as well as B1 fractions, while a decline observed in TP, B2, B3 and C fractions (P<0.05). Also, DMD of ensiled amaranth was significantly less than that for fresh forage. On the other hand, it was found that addition of molasses into the silage decreased CP, TP and as well B2, B3 and C fractions, while increasing A and B1 fractions as well as digestibility coefficients (P<0.05). It is finally concluded that based on the moderate CP value and good digestibility, amaranth benefits from the potential as a recommendable livestock forage. Ensiling process decreased digestibility and protein quality, however, addition of molasses to the silage improved the fermentation quality of the final ensiled product.

The precision and accuracy of National Research Council (NRC 2001) vs. Cornell Pennsylvania Miner (CPM) softwares were evaluated. Sixteen lactating dairy cows (8 in second lactation and 8 in third, with days in milk of 55 ± 31, body live weight = 641 ± 53 Kg, milk yield =31.2 ± 2.5 Kg/day), were assigned to individual pens in a randomized complete block design, with two blocks of two ration treatments (each treatment including 4 cows in second lactation and 4 in the third). The cows were fed rations formulated by NRC 2001 (A) and CPM (B), as totaly mixed rations (TMR) for 90 days. The adaptation consisted of a period of two weeks from the beginning of the experiment. The average milk yields of cows fed with diet A vs. B were 31.11 and 31.9, respectively with no significant difference observed between the two groups for the mentioned trait (p>0.05). There was no significant difference observed for dry matter intake (DMI) in the two ration treatments (p>0.05), the average dry matter intake of diets A vs. B being 22.9 and 22.33 Kg/day, respectively. Both NRC 2001 and CPM underpredicted DMI (-0.63 and -2.43 Kg/day respectively) while the National Research Council model predicting DMI somehow more accurately (in lactating dairy cows) than CPM. Average daily crude protein intakes for diets A vs. B were 3618 and 3438 g/d, respectively (P<0.05). An economical comparison of formulated rations by NRC 2001 vs. CPM (for the costs of feed per unit milk yield) showed a significant difference (1430 vs. 1250 Rails for NRC2001 and CPM, respectively) (p<0.01). CPM predicted a lower protein requirement than NRC 2001 with no negative effect being observed on milk yield or on any other traits. According to the results of the present study, the use of CPM is recommendable in formulating rations for the lactating dairy cows

An experiment was conducted to study the effect on performance of silkworm Bombyx mori L., when fed by leaves of different mulberry varieties a CRD design with 12 tratments (including Kamasari, Kaeiryo Ichinose, Kaeerizhotezomigaeeshi, Tachibana, Ichinose, Chekemaoha, Yukishinogi, Shin Ichinose, Wasemidori, Roso, Kenmochi, as well as some local varieties in 4 replications. The larvae were reared under standard rearing protocols. Larval feeding and mounting durations, cocoon and such pupae traits as produced cocoon number; good, middle, low and double cocoon number, pupae vitality, and weight of cocoon types were recorded. Results showed that the nutritional effect of feeding of leaves of different mulberry varieties were significant on most investigated traits (P<0.01). The results showed that feeding with leaves of Shin Ichinose variety resulted in the highest cocoon weight of 10000 larvae, the highest average weight of a best cocoon, the highest larval weight in the 4th and 5th instar, the highest vitality percentage of pupae in the best cocoons along with the lowest larval period (P<0.01). On the other hand, larvae feding with local varieties, despite obtaining the highest average cocoon shell weight and the highest average cocoon shell percentage, resulted in the lowest vitality percentage of pupae in total cocoons, along with the longest larval period of mature larvae (P<0.01). Feeding, using Tachibana and Yukishinogi variety leaves resulted in the lowest cocoon weight of 10000 larvae, the lowest average shell weight of a best cocoon, the lowest larval weight and the longest larval period (P<0.01). Also Roso variety ended up with the lowest vitality percentage in best cocoons, the lowest number of cocoons and the lowest weight of best cocoons. Thus, Shin Ichinose variety was introduced as the most suitable variety while Tachibana, Yokishinogi and Roso varieties introduced as the undesirable ones.

Fifty six Holstein lactating cows (71 days in milk; 35 Kg/day milk production) were employed in a complete block randomized design of repeated measurements. Cows were randomly allocated to two treatments based on their parity. Cows in group 1 were fed a balanced total mixed ration (600 g concentrate /kg DM and 400 g forages /kg DM) with 50 g Rumen Protected Methionine (RPM) per head per day (Methioplus 55%), while cows in group 2 were fed TMR without additive (control group). The experimental period was 40 days with 10 initial days for adaptation. RPM had no effect on milk production, milk composition and dry matter intake. Milk composition namely fat, protein, lactose, solid non fat and total solid percentage did not change by treatment (P>0.05). Cows treated with RPM bore a higher concentration of plasma glucose, and a lower plasma concentration of nonesterified fatty acids (NEFA; P<0.05). Cows in the two groups did not differ in body condition score changes during the experimental periods. It was concluded that RPM increased plasma glucose, decreased NEFA concentration, and can lead to a decrease in the incidence of ketosis and fatty liver in early lactation cows via improving liver function in fat metabolism and gluconeogenesis.