Study on effect feedings with probiotics in increasing resistance to Aeromonas hydrophila and Changes in gut bacterial communities Sander lucioperca

Introduction: This study evaluated the effect of dietary administration Lactobacillus brevis MF01 on survival rate of total bacteria, lactic acid bacteria intestinal tract fish and changes in gut bacterial communities Sander lucioperca. Materials and methods: Lactobacillus brevis was isolated and identified from intestine of Sander luciopercaby biochemical and molecular tests.Fish were fed with dietary administration containing A1 (L.brevis MF01 10 10 CFU / g), A2 (L. brevis MF01 10 8CFU / g) and the control group (without Lactobacillus) for 45 days. At the end of the feeding period, fish were challenged with 4.5× 10 8CFU /ml Aeromonas hydrophila. The intestinal micro biota includes lactic acid bacteria and total bacteria at different times (15,30, 45 days) and 15 days after stopping feedings with probiotics were performed by using MRS agar, Plate count agar media. Results: The lactic acid bacteria levels were significantly increased compared to the control group following probiotics administration in diet (P,< 0.05). The highest number of intestinal micro biota was observed in Lactobacillus brevis 1010Cfu /g treatment (A1)(P < 0.05). Any lactic acid bacteria of the intestine, was not detected in the control group after 15 days. After the end of feeding, the number of total bacteria and Lactic acid bacteria in all groups was decreased. The highest and lowest survival rate, respectively were treatments A1 (86%) and the control group (60%). Discussion and conclusion: The results showed that addition of Lactobacillusbrevis as an additive in feeding of sander lucioperca, significantly increased the lactic acid bacteria, the intestinal bacteria and the survival rate was compared to the control group (injected)

Vacuolating encephalopathy and retinopathy associated with a nodavirus-like agent: a probable cause of mass mortality of wild Golden grey mullet (Liza aurata) and Sharpnose grey mullet (Liza saliens) in Iranian waters of the Caspian Sea

Mullets are dominant fishes in the catch composition in the southern coasts of the Caspian Sea and after (Rutilus frisii kutum Kamensky, 1901) have a worthy role in production of marine proteins and incomings of north provinces of Iran. Mullets stocks decreased dramatically in recent decades in the Caspian Sea and catch amount reached from 6446 MT on 2002 to 2151 MT in 2012. Mysterious mortalities occurred in wild mullet (Liza auratu) and (Liza saliens) in Iranian waters of Caspian Sea in recent years. Regarding to investigation of causative agent of mentioned outbreak about 322 suspected samples were collected from coastal capture sites of Iranian north provinces in 2008 till 2011. Moribund fish revealed skin darkening, erratic swimming, belly-up at rest and high distension of swim bladder. Target tissues such as brain and eye were removed and then fixed for histopathology and TEM assay. Widespread and massive vacuolation were observed in brain, spinal cord, retina and optical nerve and intracytoplasmic vacuoles and virus particles in retina. So concerning to clinical signs, histopathological and TEM findings, it could be concluded that nodavirus-like agent could be probable cause of mass mortality of wild mullet in Iranian waters of the Caspian Sea