Effects Of Bovine Lactoferrin On The Immune Function And Intestinal Microflora Of Chinese Mitten Crab (eriocheir Sinensis)

Many studies indicate that bovine lactoferrin (LF) was an immunostimulant to increase the immune ability of human and animal. However, bovine lactoferrin influencing the immune abiity of the Chinese mitten crab (Eriocheir sinensis) and intestinal microflora have not been reported.In order to determine the immunomodulatory effects and intestinal microflora of bovine lactoferrin in the Chinese mitten crab (Eriocheir sinensis), the experiment one was processed. The crab were fed diets containing Lf at 0(control), 0.1, 0.3, 0.7, 1.0, 2.0, 5.0 g/kg for 4 weeks. A series of immunology parameters and intestinal microflora were examined at 1, 2, 3, and 4 weeks after administration of LF. The Crab were challenged with a virulent strain of Aeromonas hydrophila (CL99920) at 1.2×10⁷ colony forming units (cfu)/kg) at the sencond sampling time (2 week), and mortalities were recorded over a 7-day period. The results demonstrated that the groups fed with lactoferrin showed a remarkble higher number of THC compared to control group. As well as the haemocyte phagocytic activity , the respiratory burst (release of superoxide anion) and polyphenol oxidase inside the cell (POS, POT), the serum parameters, including phenoloxidase (PO), nitric oxide synthase (NOS), peroxidase(POD), catalase(CAT), acid phosphatase (ACP), alkaline phosphatase (ALP), and the serum and hepatopancreas'Super Oxide Dlsmutase(SOD) and antibacterial vigor increased significantly. The activities of Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase of muscle were significantly increased than the control (P<0.05); Alanine aminotransferase(GPT), aspertate aminotransferase(GOT) of serum and hepatopancreas reduced significantly.But differential haemocyte cout (DHC), lysozyme (LSZ) in the serum and hepatopancreas were not significantly changed (P>0.05). The immunology parameters , such as THC, the haemocyte phagocytic activity, PO, NOS, SOD, POD, CAT and antibacterial vigor were senstive to Lf. Intestinal microflora results showed: dietary administration of LF could significantly increase the number of Anaerobic formers and Bifido-bacterium (P<0.05), and decrease the number of Aerobic bacteria and Aeromonas (P<0.05) in Eriocheir sinensis's intestinal canal . Immune protection result shows: Eriocheir sinensis fed a diet containing LF have an increase ability in resistance against Aeromonas hydrophila .The results showed that supplementing 0.7g/kg LF has a significantly impact in most of the immune indexs, intestinal microflora disease resistance.