Marron

Abstract: Despite the lack of significant development of freshwater crayfish farming elsewhere in Australia, in 1980 a group of enterprising farmers from south-east Queensland introduced the Western Australian marron (Cherax tenuimanus) which they surmised would perform well under the warmer and more equable Queensland climate. Some success and expansion of the industry was achieved until the particularly warm summer of 1986, when the bulk of the marron died. Even prior to this natural disaster, some farmers were looking for alternative species, better suited to the sub-tropics. A relatively unknown crayfish from north Queensland, Cherax quadricarinatus entered the scene and commercial trials in ex-marron ponds began. It was soon evident that this species had a substantially greater potential.

Abstract: This study aimed to investigate the combined effects of two most potent probiotic bacteria Lactobacillus acidophilus and Lactobacillus plantarum on overall health and immune status of freshwater crayfish, marron under laboratory conditions. A total of 36 marron were distributed into six different tanks and two different feeding groups, control and probiotic-fed group. After acclimation, control group was fed with basal diet while probiotic group was fed 109 CFU/mL per kg of bacterial supplemented feed for 60 days. The results showed no significant differences in weight gain, however, probiotic feed significantly enhanced some hemolymph parameters and biochemical composition of tail muscle. Histology data revealed better hepatopancreas health and higher microvilli counts in the marron gut fed probiotic diet. The probiotic bacteria triggered significant shift of microbial communities at different taxa level, mostly those reported as beneficial for crayfish. The probiotic diet also enriched the metabolic functions and genes associated with innate immune response of crayfish. Further correlation analysis revealed significant association of some taxa with increased activity for hemolymph and immune genes. Therefore, dietary Lactobacillus supplementation can modulate the overall health and immunity as well as gut microbial composition and interaction network between gut microbiota and immune system in crayfish.