فصلنامه دامپزشکی ایران
سال هشتم شماره 34 (بهار 1391)

In order to assess the effect of increasing levels of dietary soybean meal and the effect of phytase enzyme supplement on apparent digestibility coefficient of diet protein, energy and dry matter and also carcass mineral composition of beluga juvenile, seven isonitrogenous and isocaloric diets containing various levels of soybean meal (40% and 70%) as gradual replacement of fish meal (Control diet) and three levels of phytase: zero, 1000 and 2000 IU/kg (not in control diet) were fed to triplicate groups of 10 fish (initial mean weight: 80.65±2.16 g) in each tank. Over an 8-week feeding period, significant differences (P<0.05) were observed on apparent digestibility coefficient and mineral composition between fish fed the experimental diets. The partial replacement of fish meal by soybean meal resulted in significantly decreasing in the apparent digestibility coefficient of diet protein and energy and also in carcass phosphorus and calcium content (P<0.05). On the other hand, the apparent digestibility coefficient of diet dry matter and the carcass magnesium content were not affected by the experimental diets (P>0.05). In addition, supplementation of phytase resulted in significant increase in the apparent digestibility coefficient of diet protein and the carcass phosphorus and calcium content (P<0.05). There were not significant difference among substitute effect, phytase effect and interaction in the apparent digestibility coefficient of diet protein, energy and dry matter and moreover in the carcass magnesium (P>0.05). However substitute effect, phytase effect had significant different in the carcass phosphorus and calcium (P<0.05). According to these results, the replacement of fish meal by soybean meal result in decrease the apparent digestibility coefficient of diet protein and energy and also in phosphorus and calcium content in beluga juvenile carcass. On the other hand, supplementations of phytase results in increase the apparent digestibility coefficient of diet protein and the carcass phosphorus and calcium content.

This study was conducted to determine the effects of different levels of betaine substitution to methionine on performance, carcass characteristics and blood compositions of Ross 308 broiler chickens reared under heat stress (HS) and thermoneutral (TN) conditions. A total of two hundred eighty eight 1-day-old commercial broiler chicks were used for this experiment in a 42 day period. Broiler chicks were grown in a thermoneutral environment from 1 to 21 d. From 22 to 42 days, 144 of the birds were kept in the thermoneutral room (TN, 23°C constant) whereas the remaining of the birds were exposed daily to cyclic stress (HS, 23 - 35°C cycling) in another room. The trial was conducted as a complete randomized design (CRD) with a 3×2 factorial arrangement of treatments with four replicates per treatment. There were 3 dietary treatments: three doses of betaine (0, 13 and 26%) substitution to methionine that were combined with two environmental conditions. Broilers raised in either a TN or HS environment were fed two types of diets as starters and growers. The present study indicated that replacement of betaine significantly affected breast meat yield. Supplementation of the basal diets with betaine were significantly affected FI, FCR, BW during 22 to 42 d and 1 to 42 d. Results showed that replacement of betaine at the levelof 13% increased FI and BW. The HS birds consumed less feed, gained less weight, and had lower feed efficiency when compared to TN birds (P<0.05). Moreover, this level improved FCR at the HS or TN bird. Breast and leg meat yield, heart and liver weights, were all significantly reduced by HS in comparison with TN (P<0.05). Evaluation of the effect of betaine and temperature showed that heat stress caused a significant increase in glucose and triglyceride; whereas, the betaine just significantly affect the triglyceride.

In the present study blood samples were collected from 90 birds in order to investigate the genetic variation of interon 4 of chicken growth hormone gene (cGH) in West Azeraijan native chicken. Genomic DNA was extracted and a fragment of 1170 bp in size was amplified using polymerase chain reaction. The amplified fragments were subjected to restriction digestion with MspI endonuclease enzyme and the resultant digested products were run on 2% agarose gel. The results revealed the existence of three alleles A, B and C for the examined locus with frequencies of 34.44%, 32.22% and 33.33% respectively. A number of six different genotypic variants including AA, AB, BB, AC, BC and CC were identified withgenotypic frequencies of 11.11%, 23.33%, 12.22%, 23.33%, 16.66% and 13.13% respectively. The expected hetrozygosity value and effective number of alleles were 0.66 and 2.99 respectively. G square and Chi square tests based on observed and expected frequenciesof different genotypic variants of cGH gene showed that deviation from Hardy-Weinberg equilibrium was not significant for West Azerbaijan native chicken. It was concluded that the genotypes of the examined locus were not affected by genotype influencing factors such as selection, migration and mutation.

Genetic population structure in four finger threadfin (Eleutheronema tetradactylum) was examined by using sequencing analysis in the Persian Gulf and Oman Sea. Forty one samples were collected from four locations; Khoozestan, Booshehr, Bandarabas and Systan and Baloochestan. Genomic DNA was extracted using Phenol_chloroform method. Forward and reverse primers were designed based on 28s rRNA gene in four finger threadfin. After PCR and sequences alignment, data statistical analysis was performed by Dnasp V:5, Arlequin V:3.5 and MEGA V:4 softwares. Maximum haplotype and nucleotide number and diversity were found in Bandarabas region and minimum of those indicators was recorded in Booshehr region. The highest genetic distance was between Booshehr and Bandarabas regions (0.29) and the lowest was between Booshehr and Chabahar (zero) regions, respectively. The highest and lowest sequence divergence were between Chabahar_Khoozestan (0.71) and Booshehr_Chabahar (0.05), respectively. Maximum haplotype frequencies rate were found between Bandarabas_Booshehr (12.37) and Booshehr_Khoozestan (7.95) populations (P<0.05). Maximum rate of haplotype and nucleotide diversity was estimated between Khoozestan_Booshehr regions and minimum for those indicators were recorded between Booshehr_Chabahar regions. Regarding the results it can be stated that Booshehr is an old population and has reached to the genetic stable structure, but the others have an aspect of high dynamic genetic population. So, all of them sets in an one cluster in phylogenetic tree and the out group was reset in another cluster.

In this experiment, the effect of PMSG on the output of estrus synchronization following using norgestomet implant was investigated in river buffaloes. Twenty two cyclic female river buffalos at unknown stages of estrus cycle were selected and received norgestomet implant (Crestar, 3mg norgestomet, Intervet, Holland), with an injection of GnRH at first day of experiment. On day 7 after norgestomet insertion, females were randomly assigned into two groups considering their age and weight and both groups of control and experiment received PG F2α (15mg prostiol, prozolin, intervet, Holland). The animals in treatment group received PMSG (Folligon, 1000IU, IM, intervet, Holland) in addition to PG F2α. The implant was removed on day 9 after insertion in all females. Estrous detection was conducted using teaser bull, from 12 hours after norgestomet removal for 7 days every 4 hours for at least 30minutes. From the beginning of sfrous until ovulation, ultrasonography was conducted at the time of estrus, 24, 32 and 40 hours after standing estrus. PMSG had no effect on the frequency of estrous response (Treatment: 100%; control: 81.8%), tightness of estrus synchrony within 12 hours (Treatment: 77/8%; Control: 72/8%) and the frequency of ovulation (Treatment: 100%; control: 88.9%; P>0.05). The interval between the end of treatment and the start of estrus in control group (52.5±4.11 hours) was longer than PMSG group (41.8±8.57 hours; P<0.05). In conclusion, PMSG injection, 2 days prior to the termination of 9 days estrus synchronizationprogram could hasten the time of estrous expression in river buffalo. This has to be considered in fixed timed artificial insemination in this species.

This study was designed to assess the effects of intracerebroventricular (ICV) injection of serotonin(5-HT), parachlorophenylalanine(PCPA) and reserpine on food and water intake in 24-h food-deprived (FD24) broiler cockerels, and also to determine that water intake is dependent or independent to food intake. At first, guide cannula was surgically implanted in the right lateral ventricle of chickens. After 5-7 days recovery period, the broilers deprived of food for 24 hours. In experiment 1, 2 and 3, birds were injected (ICV) with different doses of serotonin, PCPA and reserpine, respectively. Fresh food and water was supplied immediately after injection and cumulative food and water intake was determined at 30, 60, 90, 120, 150 and 180 minutes postinjection. The results of this study showed that serotonin decreases food intake and increases water intake in FD24 broiler cockerels (P<0.05); while the effects of PCPA and reserpine were inverse of serotonin. These data indicate the possibility of central 5- HT involvement in regulation of food and water intake in chickens and seems that the effect of serotonin on food and water intake in chickens is independent of each others.

Incidence of Lactococcus garveiae the causative agent of lactococcosis was studied in 32 rainbow trouts farms in Chaharmahal-va- Bakhtyari province during 2009. Totally 192 bacterial isolates were obtained from kidney tissues of the clinically affected fish on blood agar at 30ºC. After biochemical tests, a number of 68 isolates were identical as L. garvieae phenotypically. Only 36 isolates were confirmed as L. garvieae using PCR analysis. The sequencing of 16S rRNA gene of some selected isolates were performed randomly and showed that these isolates have the most relationship with the isolates from China, Japan and Australia while, less relationship was found with the Tunis isolates. These results show that incidence of lactococcosis (streptococcosis) caused by L. garvieae increased in the rainbow trout farms in Chaharmahal-va- Bakhtyari province during 2009, in comparison with previous years.

In order to study development of nephrons in larval and fingerling stages of sturgeon (Acipenser persicus), a total number of 60 samples of larvae and Fingerlings were randomly collected and immediately were fixed in Buin’s fluid. After routine histological procedures and sectioning at 5-6 micrometers, they were stained with hematoxylin and eosin and studiedunder light microscope. The results showed that in one day after hatching, the abdomen was filled with yolk sac which was disappeared in the next days and the growth of organs was developed. Renal corpuscles were observed during the first week. Renal corpuscles and urinary tubules were obvious after fourth day of hatching. During the next days, the kidneys progressed gradually to the caudal parts and also the tubules and renal corpuscles increased in number. Also in days twenty to twenty five, beside the growth and increasing of renal corpuscles, complete differentiation of urinary tubules occured. In days thirty five to forty complete growths of tubules and renal corpuscles were observed, moreover each tubule showed its own cytoplasm staining, and the presence of hematopoietic tissues and lymphatic tissues were completely obvious.