Abstract:Sheep is the common name for a group of grazing mammals that may be either wild or domesticated; the domesticated varieties are amongst the most widely distributed types of domestic animal, found in nearly all countries. Bangladesh is a densely populated developing country and its economy is primarily based on agriculture. The current study was designed for isolation, identification and characterization of bacterial flora from the upper respiratory tract of sheep. Thirty (30) apparently healthy sheep were selected at the adjacent areas of Bangladesh Agricultural University (BAU) for this experiment. Swab samples were collected from nasal swabs (10), lung swabs (10) and tracheal swabs (10). All samples were subjected into inoculated on to bacteriological media (nutrient broth, nutrient agar, Salmonella-Shigella agar, MacConkey agar, blood agar, brilliant green agar). Furthermore, all of the bacterial isolates were characterized by Gram's staining, biochemical tests (sugar fermentation tests, catalase test, coagulase test, indole test, MR-VP test), antibiotics sensitivity tests and pathogenicity tests. None of the isolated Bacillus, E. coli and Staphylococcus spp. was found to be pathogenic. Isolated Pasteurella spp. were found to be pathogenic as observed in different experimental models and showed a degree of variation in antibiotic drug sensitivity test. Ciprofloxacillin was sensitive to all of the isolated bacteria. Through the bacteria that were isolated from various organs of apparently healthy sheep is normal micro flora, however these may act as primary pathogen and may produce diseases when the sheep are immunologically suppressed due to severe stress conditions.

Male germ cells undergo complex developmental processes eventually producing spermatozoa through spermatogenesis, although the molecular mechanisms remain largely elusive. We have previously identified somatic cell nuclear transfer-reprogramming resistant genes (SRRGs) that are highly enriched for genes essential for spermatogenesis, although many of them remain uncharacterized in knockout (KO) mice. Here, we performed a CRISPR-based genetic screen using C57BL/6N mice for five uncharacterized SRRGs (Cox8c, Cox7b2, Tuba3a/3b, Faiml, and Gm773), together with meiosis essential gene Majin as a control. RT-qPCR analysis of mouse adult tissues revealed that the five selected SRRGs were exclusively expressed in testis. Analysis of single-cell RNA-seq datasets of adult testis revealed stage-specific expression (pre-, mid-, or post-meiotic expression) in testicular germ cells. Examination of testis morphology, histology, and sperm functions in CRISPR-injected KO adult males revealed that Cox7b2, Gm773, and Tuba3a/3b are required for the production of normal spermatozoa. Specifically, Cox7b2 KO mice produced poorly motile infertile spermatozoa, Gm773 KO mice produced motile spermatozoa with limited zona penetration abilities, and Tuba3a/3b KO mice completely lost germ cells at the early postnatal stages. Our genetic screen focusing on SRRGs efficiently identified critical genes for male germ cell development in mice, which also provides insights into human reproductive medicine.

The present study was designed with a view to study the effects of enrofloxacin antibiotic on ISA brown layer performance. A total of 1,80,000 laying hens (ISA brown) received and supplied enrofloxacin antibiotic in the dose of 0 mg, 10mg and 20 mg/kg BW with normal diet. Each layer was fed 120 g feed/day from 42 to 48 weeks of age. Antibiotic made significant differences in egg production (p<0.05) and especially on mortality (p<0.01). The different doses of enrocin (0 mg, 10mg and 20mg/kg BW) had no significant effect on feed conversion efficiency and egg weight. Therefore, it can be suggested that a lower dose (10mg/kg BW) of antibiotic may be benefited in commercial layer diet.

A research work was undertaken to evaluate the feeding effect of tree forages on performance of growing sheep. Twenty growing sheep (in 4 groups) were fed three different tree forage diets. Tree forages Melia azardirachta, Leucaena leucocephala and Artocarpus heterophyllus were supplied in three treatments except one consisted no tree forages which was considered as control. There were significant (p<0.05) differences among the animal groups in terms of total DM and ME intake, although there were no significant differences in the digestibility of DM, OM, CP and ADF. Feeding of tree forages had significant (p<0.05) effect on live weight gain of sheep. Animals fed with tree forage based diets significantly increased weight gain (60.70 and 50.70 g/d for L. leucocephala and A. heterophyllus, respectively) compared to that (45.66 g/d) of control group fed with silage. Feed conversion efficiency (kg feed/kg gain) also showed that animals fed with tree forage of L. leucocephala and M. azardirachta based diets were having significantly (p<0.05) higher efficiency (11.33 and 11.47, respectively) compared to those of A. heterophyllus and control diet (13.77 and 13.33, respectively). The results of nitrogen balance of M. azardirachta and L. leucocephala tree forage had significantly (p<0.05) positive effect on the nitrogen retention in the body of the animals. Intake of all the tree forages was not similar which indicated that all of them were not accepted to the lamb in same level. So, diets with tree forages of L. leucocephala resulted better in terms of weight gain, digestibility and nitrogen balance compared to A. heterophyllu, M. azardirachta and silage (control).Asian J. Med. Biol. Res. December 2015, 1(3): 648-653