Fish Genetics & Biotechnology


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Mehak Hafeez



Virulence gene profiling of Clostridium perfringens from fish and aquatic environment of Dal Lake

Dr. Irfan Ahmad

During the current study, the presence of different toxinotypes of Clostridium perfringens in the icthyofauna particularly Cyprinus carpiovar. communis (Scale-carp) and Schizothorax niger (Snow-trout) and the aquatic environment of the Dal Lake was investigated. A total of 165 samples (60 each of scale-carp and snow-trout; 45 water), collected from different sites of Dal Lake, were screened for the presence of C. perfringens. Using species-specific 16S rRNA gene amplification, all the 45 (100%) water samples and 37 (30.8%) of 120 fish samples were found to be positive for C. perfringens. The toxinotyping of C. perfringens isolates carried out by multiplex-PCR targeting six toxin genes (cpa, cpb, εtx, ιtx, cpb2 and cpe) revealed that all the 45 isolates from water and 37 isolates from fish (21 from scale-carp and 16 from snow-trout) were carrying cpa gene and thus were designated as toxinotype A. None of the isolates carried other toxin genes like cpb, εtx, ιtx, cpb2 or cpe. It was also observed that the prevalence of C. perfringens was slightly higher in scale-carps (35%) compared to snow-trouts (26.6%). During the present study, the bacterial load of C. perfringens at five different sites of the Dal Lake was calculated and was found to be in the range of 9.2 x 10 CFU/ml to 1.87 x 10 2 CFU/ml, being lowest at Char-Chinari and highest at Dalgate, which is less than the critical CFU level of C. perfringens. Antibiotic sensitivity test of C. perfringens type A isolates revealed high resistance to more than 3 antimicrobials with amoxicillin/clavulanic acid, chloramphenicol and ciprofloxacin as being most sensitive. The cpa toxin genes of C. perfringens type A isolates obtained from water and fish sources during the study were sequenced and the outline of phylogenetic tree revealed 95% to 98% homology with corresponding GenBank published sequences. The phylogenetic analysis of the protein sequences of cpa toxin revealed a close relationship with corresponding AA sequences of C. perfringens strains reported from India, Egypt and China. The present study documented the presence of C. perfringens toxinotype A in fish and water for the first time in the Dal Lake of the Kashmir valley and implied that fish may be a possible source of C. perfringens type A intoxication to humans through food chain.


Sumaira Rashid



Detection of cytochrome P450 in fishA potential biomarker of aquatic environmental contamination


Dr. Irfan Ahmad

The present study was carried out to detect and quantify cytochrome P4501A in Cyprinus carpio var. communis collected from Dal Lake. Physico-chemical parameters, viz., Water temperature, pH, Total Phosphorus, Ammonical Nitrogen and Nitrate Nitrogen were also monitored during the study. Samples were collected from two different sites of the Dal lake viz. Nishat and Hazratbal basin and experimental control from December 2018 to March 2019. Samples were collected on monthly basis. Cytochrome P4501A was detected in all the samples examined throughout the study. Using one way analysis of variance, P<0.01 was obtained which indicated that there was a significant difference (P<0.05) in CYP1A levels among the 3 sampling sites viz., Hazratbal, Nishat and control. Further, it was observed that CYP1A showed the +ve correlation with both total phosphorus (r=0.30, P>0.05) as well as nitrate nitrogen (r=0.07, P>0.05). Both CYP1A level as well as the total phosphorus and nitrate levels was highest in samples collected from Hazratbal basin and lowest in the samples collected from control. Limnological parameters were found in the range of: total phosphorus (86-746μg/L), nitrate nitrogen (80-387μg/L), water temperature (7-12.3 ºC), pH (7-7.7), ammonical nitrogen (46-444μg/L).





Assessment of the growth performance by RNA:DNA ratio in Cyprinus carpio var. communis (Scale carp)using different dietary protein levels


Dr. Irfan Ahmad

Silkworm pupae is a high-quality insect protein source with a rich and balanced content of amino acids. The present growth trial was conducted on scale carp fingerlings (Cyprinus carpio L. var. communis) fed with three  different levels of silkworm pupae supplement [17.51 g/100g (T1), 14.42 g/100g (T2), 11.33 g/100g (T3)] with a control in which no silkworm pupae was included. The aim of the study was to  determine the RNA: DNA ratio as an indicator of growth performance in common carp after fed with dietary protein level . RNA:DNA ratio were  highest in T1(1.609), followed by T2(1.526) and T3(1.239) while the control showed the lowest ratio (0.929). Similarly fingerlings fed with Silkworm pupae supplemented diets (T1, T2 and T3) exhibited relatively better growth in terms of body weight gain, percent  weight gain, specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) as compared to the control . The highest weight gain of 2.4 g was recorded in T1followed by T2(2.09 g) and T3(1.52 g) while the control achieved the lowestweight gain of 0.72 g. Overall, the results revealed that T1 performed better as compared to the rest treatments and control. In general, the RNA :DNA ratio and growth results correlate with each other in different treatments and control. So, RNA: DNA ratio confirms to be as an effective and rapid indicator of growth performance