Wanaporn Tapingkae

Natrinema gari sp. nov., a halophilic archaeon isolated from fish sauce in Thailand

Two Gram-negative, rod-shaped, halophilic archaea, designated strains HIS40-3(T) and HDS3-1, were isolated from anchovy fish sauce (nam-pla) collected from two different locations in Thailand. The two strains were able to grow at 20-60 degrees C (optimum 37-40 degrees C), at 1.7-5.1 M NaCl (optimum 2.6-3.4 M NaCl) and at pH 5.5-8.5 (optimum pH 6.0-6.5). Hypotonic treatment with less than 1.7 M NaCl caused cell lysis. The major polar lipids of the isolates were C(20)C(20) and C(20)C(25) derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, two glycolipids and one unidentified lipid. The DNA G+C contents were 64.0-65.4 mol%. In addition to phenotypic and chemotaxonomic characteristics, phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strains HIS40-3(T) and HDS3-1 were related most closely to species of the genus Natrinema. Levels of 16S rRNA gene sequence similarity between strains HIS40-3(T) and HDS3-1 and the type strains of recognized Natrinema species were 99.1-96.6 %. The two novel strains could be distinguished from recognized Natrinema species on the basis of low levels of DNA-DNA relatedness and differences in whole-cell protein patterns and phenotypic properties. Levels of 16S rRNA gene sequence similarity and DNA-DNA relatedness between the two strains were 99.7 and 77.7 %, respectively, suggesting that they should be classified as representing a single species. Based on these taxonomic data, strains HIS40-3(T) and HDS3-1 are considered to represent a novel species of the genus Natrinema, for which the name Natrinema gari sp. nov. is proposed. The type strain is HIS40-3(T) (=BCC 24370(T) =JCM 14663(T) =PCU 303(T)).

The effects of dietary kefir and low molecular weight sodium alginate on serum immune parameters, resistance against Streptococcus agalactiae and growth performance in Nile tilapia (Oreochromis niloticus)

ABSTRACT The present study evaluates the effects of dietary kefir and low molecular weight sodium alginate (LWMSA) (singular or combined) on non‐specific immune response, disease resistance and growth performance of Nile tilapia (Oreochromis niloticus). Fish with average weight of 18.60 ± 0.04 g were supplied and randomly stocked in sixteen glass tanks (150 L) at density of 20 fish per tank. Fish were fed experimental diets as follows: 0 g kg−1 LMWSA (Control, Diet 1), 10 g kg−1 LMWSA (Diet 2), 40 g kg−1 kefir (Diet 3), and 10 g kg−1 LMWSA + 40 g kg−1 kefir (Diet 4) for 50 days. At the end of the feeding trial, serum lysozyme (SL), phagocytosis (PI), respiratory burst (RB), and alternative complement (ACH50) activities as well as growth performance were measured. Singular and combined administration of kefir and low molecular weight sodium alginate (LMWSA) significantly increased serum SL, PI, RB, and ACH50 activities compared control group (P < 0.05); the highest innate immune responses were observed in fish fed combinational diet (kefir + LMWSA) (P < 0.05). The results of experimental challenge revealed significantly higher resistance against Streptococcus agalactiae in fish fed supplemented diets and the highest post challenge survival rate was observed in synbiotic diet (P < 0.05). Similar results obtained in case of growth parameters. Feeding on supplemented diet significantly improved SGR and FCR and the highest growth parameters was observed in fish fed synbiotic diet (P < 0.05). These finding revealed that combined administration of dietary kefir and LMWSA can be considered for improving immune response, disease resistance and growth performance of Nile tilapia. HighlightsDietary administration of 10 g kg−1 LMWSA and 40 g kg−1 kefir significantly improved growth performance.Nile tilapia fed 10 g kg−1 LMWSA and 40 g kg−1 kefir significantly stimulated immune response, and disease resistance.Combination of kefir and LMWSA stimulated immunity, disease resistance, and growth performance of fish.

Effects of Cordyceps militaris spent mushroom substrate on mucosal and serum immune parameters, disease resistance and growth performance of Nile tilapia, (Oreochromis niloticus)

Abstract The aim of present study was determination effects of dietary administration of C. militaris spent mushroom substrate (SMS) on mucosal and serum immune parameters, disease resistance, and growth performance of Nile tilapia (Oreochromis niloticus). Two hundred twenty five fish of similar weight (37.28 ± 0.10 g) were assigned to the following diets [0 (T1‐ Control), 5 (T2), 10 (T3), 20 (T4) and 40 g kg−1 (T5) SMS]. After 60 days of feeding trial, growth performance, skin mucus lysozyme and peroxidase activities as well as serum innate immune were measured. In addition, survival rate and innate immune responses were calculated after challenge test (15 days) against Streptococcus agalactiae. The results revealed that regardless of inclusion levels, feeding Nile tilapia with SMS supplemented diets significantly increased skin mucus lysozyme and peroxidase activities as well as serum immune parameters (SL, ACH50, PI, RB, and RB) compared control group (P < 0.05). The highest increment of immune parameters was observed in fish fed 10 g kg−1 SMS which was significantly higher than other treatments (P < 0.05). Also, the relative percent survival (RSP) in T2, T3, T4, and T5 was 61.11%, 88.89%, 66.67, and 55.56%, respectively. Among the supplemented groups, fish fed 10 g kg−1 SMS showed significant higher RPS and resistance to S. agalactiae than other groups (P < 0.05). Regarding the growth performance, SGR, WG, FW, and FCR were remarkably improved (P < 0.05) in SMS groups; the highest improvement observed in 10 g kg−1 SMS treatment. According to these finding, administration of 10 g kg−1 SMS is suggested in tilapia to improve growth performance and health status. HighlightsTilapia fed 10 g kg−1 SMS significantly stimulated mucosal and serum immune response.Diet of 10 g kg−1 SMS significantly increased survival rate of O. niloticus against S. agalactiae.Fish fed 10 g kg−1 SMS significantly enhanced growth performance and feed conversion ratio.