مجله تولیدات دامی
سال چهاردهم شماره 1 (بهار و تابستان 1391)

This study was conducted to determine the nutritional value of seaweed Gracilariopsis persica and to evaluate its utilization in layer nutrition. Metabolizable Energy and chemical composition of seaweed were measured. 100 Hy-line W-36 hens were allocated to five dietary groups with five treatment group (experimental diets containing zero, five, 10, 15 and 20 percent seaweed) and it lasted for 12 weeks. Egg production, feed intake, feed conversion ratio, egg weight and egg mass were measured weekly. The results showed that the CP, CF, EE, Ca and P of the seaweed were 23.05, 7.2, 0.1, 0.9 and 0.34 percent, respectively. Apparent Metabolizable Energy and Apparent Metabolizable energy corrected for nitrogen were 2185.04 and 2195.72 Kcal/Kg, respectively. The treatments contain more than five percent seaweed, decreased egg production and increased feed conversion ratio (P< 0.05). There was significant decrease in egg mass for more than 10 percent seaweed treatments (P< 0.05). These results showed that usage of five percent seaweed Gracilariopsis persica in the layer hen's diet doesnt have negative effect on production performances.

The study was consequently investigated effect of different tanning methods on apparent density, thickness, tensile strength and also extension percentage in three different tanning (chromic, alum and vegetable) of grown part of ostrich skins (n = 15; 12 to 14 months). Average apparent density and thickness of leathers were 0.7 ± 0.0gr/cm2 and 1.7 ± 0.1 mm, respectively. The breaking load, tensile strength and extension of chromic tanning leather (33.0 ± 4.9 kgf, 197.2 ± 23.9 kgf/cm2 and 53.3 ± 7.0 percent) were more than alum tanning leather (27.4 ± 5.5 kgf, 161.7 ± 26.7 kgf/cm2, 46.4 ± 7.8 percent) and vegetable tanning leathers (13.0 ± 4.5 kgf, 70.7 ± 21.8 kgf/cm2 and 40.1 ± 6.4 percent). However, the best physical quality was found in the chromic tanned leather for ostrich skin proccesing related to alum and vegetable leathers.

The effects of days in milk (DIM) on the curves of milk yield and milk fat percentage in Holstein cows of Iran were studied. A total of 964,606 and 885,346 test day records were used for milk yield and milk fat percentage, respectively. The data were grouped in four classes including: 1) 240 < DIM < 301, 2) 300 < DIM < 401, 3) 400 < DIM < 501 and 4) 500 < DIM < 601 days. To fit the curves, nine non-linear models for every one of the classes were applied. The Narushin & Takma 1 function which previously has been used for fitting the production and growth characteristics of chickens was used in this study. It showed a relatively high goodness of fit in fitting milk yield and milk fat percentage curves compared to other functions. Wood, Dijkstra and Rook functions showed higher Adjusted R2 whereas the third order Legendre polynomial function showed the lowest value in all the classes. The cows had longer lactation period, showed higher persistency and yielded higher daily milk at peak and post peak stages of lactation period. The forth class of cows yielded considerably higher milk and fat (based on 305 day production) compared to other groups. On the contrary, the rate of reduction of milk yield was significantly high for cows located in the lowest lactation length class and the slope of declining stage of milk yield curve was sharper.

20 one-month-old Sanjabi suckling lambs (ten males and ten females with initial liveweight of 13.4 ± 1.3 and 11.6 ± 0.9, respectively) were used to assess the effect of ad libitum creep mixture on dry mater intake, live weight gain and carcass characteristics. The lambs were blocked within sex according to their live weight and randomly allocated to one of two treatments, control (free suckling and free choice of alfalfa) or supplementary (ad libitum creep mixtures with free suckling and free choice of alfalfa) in a 2 × 2 factorial arrangement. The study was continued for 100 days and at the end of the experimental period, all lambs were slaughtered to assess carcass characteristics. Average daily milk intake of males was higher than females (P< 0.01). Daily live weight gain (g/d) was significantly (P< 0.01) higher in males than females (240 vs. 163 g/d) and in the supplementary group than the control (259 vs. 145 g/d). Fat tissue in both male and female lambs in supplementary group was significantly (P< 0.01) more than that in the control. It could be concluded that the creep mixture diet improved growth rate and carcass characteristics and the fat content of the lambs.

Forty sheep skins were allocated into two groups. Group one was sheared using shearing machine and group two was chemically dewooled using 15 percent sodium sulfide. Results indicated that fibre diameter of slipewool (39.3 ± 2.3 µm) was significantly (P< 0.05) higher than the sheared wool fibers (36.3 ± 0.7 µm), but staple length of slipewool (3.3 ± 0.7 cm) was significantly (P< 0.05) lower than the sheared wool fibers (5.3 ± 0.2 cm). Percentage of relative length increase in yarns of slipewool was significantly (P< 0.05) higher than the sheared wool fibers. Staple strength of yarns made from slipewool was 1.7 gf/t which was considerably different from yarns made of sheared wool (2.1 gf/t). Percentage of color absorption, washing color fastness, light color fastness of yarns made of slipewool was considerably different from similar value of sheared wool. Thickness of carpets under dynamic and static force of the yarn made from slipewool (88.00 and 88.40 unit) was different from that of yarn made from sheared wool (93.09 and 91.46 unit). Use of slipewool in hand-woven carpet should be avoided due to decrease in yarn strength, color fastness and increased in color absorption. Other methods of skin dewooling should be considered.

The transforming growth factor B (TGFB) subfamily is one of the most important groups of genes that are involved in development of growth and cell differentiation. In order to detect polymorphism in TGFB3 loci, blood samples were collected randomly from 160 breeder hens of Mazandarn native fowls breeding station. DNA was extracted using modified salting out method and a DNA fragment of 295 bp from TGFB3 loci was amplified (part of intron 3, exon 4 and small part of intron 4) using a specific primer pairs. The digested amplified fragment with BsiYI enzyme revealed two + and – alleles with the frequency of 0.8037 and 0.1961, respectively. The frequencies of "+/+", "+/-" and "-/-" genotypes were estimated at 0.6645, 0.2784 and 0.0569, respectively in studied population. The statistical analysis showed that the existence of one + allele in the genotypes significantly (P ≤ 0.05) increased the means of body weight at one day and eight week of age in comparison with "-/-" genotype which indicates the importance of this allele in body weight gain in chickens. It can be concluded that the studied marker site, together with the other documented variants in TGFB3 locus, can be very useful to obtain a better understanding of the genetic control of growth rate in chickens.

The effect of replacement of soybean meal protein with low glucosinolate rapeseed meal was investigated in an experiment with 320 one-week old broilers with an average live weight of 111 g. Chicks divided into two groups and each further subdivided into four subgroups. To each subgroup, four cages of 10 chicks per cage allocated. 30 and 45 percent of soybean meal protein of the diet of group (1) and group (2) replaced with rapeseed meal respectively. Levels of enzyme were zero, 500 units of phytase, 600 units Safizym GP 800 and a mixture of 500 units of phytase and 600 units of Safizym GP 800 added to the diets. Results showed that the interactions of levels of rapeseed meal and enzymes on the feed conversion and live weight gain were significant. In 30 percent replacement level, the best feed conversion (1.8) were belong to diets with no enzyme and in 45 percent of replacement, the feed conversion of diets with no enzyme (2.43) were higher than the diets with mixture of enzyme (2.03). The lowest values of live weight gain in the total period (42.30 g) was belonged to 45 percent replacement of rapeseed meal without enzyme. Overall result shown that the rapeseed meal can be used to provide 30 percent of the diet protein but in the case of adding enzyme to the diet, up to 45 percent of protein can be provided by the rapeseed meal.