Research Article
F Lombardo, G Gioacchini, O
Abstract
Probiotic bacteria used as dietary additives seem to offer an attractive choice inducing overall health benefits to the host organism. It is well known that reproduction, in all vertebrates, is regulated by the reproductive axis and that nutrition affects reproductive events, from puberty to adult gametogenesis, in both sexes. Consequently, reproductive events are very closely aligned with the nutrition. The aims of this study were to investigate the effects of dietary probiotic administration on the marine teleost Fundulus heteroclitus and the effects of such broodstock dietary treatment on the growth and survival of the new progeny. Lactobacillus rhamnosus IMC 501® was administered daily as a feed additive, at a final concentration of 106 cfu ml-1 for 8 days. Gonadal growth (gonadosomatic index, GSI), fecundity, embryo survival and hatching rate of larvae from broodstock fed probiotic-supplemented diets were analysed as well as the biometric parameters (body weight, BW; total length, TL). The results demonstrated the beneficial effects of probiotics on the reproductive performance of this marine teleost, as the GSI, fecundity and embryo survival were significantly enhanced by probiotic administration. On the contrary, no effect on the hatching rate was shown. Moreover, broodstock probiotic-based nutrition affected the early stages of larval development of the new progeny: in detail, a significantly higher TL was shown throughout the experiment in the progeny derived from the probiotic (PRO) group bloodstocks compared to the control (CTRL) group; mean BW was significantly higher only at 30 days post-hatching (dph) while no change was observed in terms of larval survival. These results confirmed the positive effect of L. rhamnosus IMC 501® on the reproductive process of this marine teleost, but further work is required to better understand the mechanisms by which probiotics act on the reproductive axis as well as the nutritionally-/immunologically-mediated maternal effects on embryo and larval development and growth.