Search

Search Results

• Impacts of Dietary Supplementation of Peptidoglycan Extracted from Lactobacillus sp. on the Growth Performance and Resistance to Streptococcus Agalactiae of Nile Tilapia

  Nguyen Thi Mai, Mai Van Tung, Do Hoanh Quan, Vu Thi Thanh Huong, Nguyen Thu Hang

  Received: Mar 14, 2023 / Published: Jun 30, 2023

   Abstract PDF

  The current experiment aimed to determine the effects of peptidoglycan, known as a prebiotic compound, on the growth, feed efficiency, and disease resistance in Nile tilapia. Fish at an initial body weight of 22.6 ± 0.3g were distributed into a 100 L-glass tank system. Peptidoglycans extracted from Lactobacillus sp. were added to commercial feed at ratios of 0, 5, and 10 g kg-1 diet corresponding to the PG0, PG5, and PG10 treatments, respectively. Fish were then fed at 4% their body weight for four weeks. After a 4-week trial, fish were infected with Streptococcus agalactiae at 50% the lethal dose (1.1×106 CFU mL-1), and monitored for 14 days. After 2 and 4 weeks of the feeding trial (T2 and T4) and on the second day of the bacterial challenge, fish blood samples were collected for hematological analysis. The results indicated that the dietary supplementation of peptidoglycan induced a positive effect on fish growth performance and the highest value was observed in the PG5 treatment. The lowest value of cumulative mortality was also observed in the PG5-fed fish indicating that the dietary supplementation at 5 g kg-1 diet supported the highest resistance to S. agalactiae. In conclusion, the beneficial effects of dietary supplementation of peptidoglycan extracted from Lactobacillus sp. were recorded on the growth performance and disease resistance in Nile tilapia.

• Evaluation of Local Black Glutinous Rice Germplasm of Vietnam for Resistance to Bacterial Leaf Blight Disease

  Hoang Tung, Phan Huu Ton, Tong Van Hai, Tran Nam Trung

  Received: Jan 08, 2019 / Published: Feb 13, 2019

   Abstract PDF

  Most rice growing areas frequently encounter the bacterial leaf blight, Xanthomonas oryzae pv oryzae (Xoo). To prevent the disease, development of resistant varieties is considered to be the most economical and environmentally safe solution. In this study, three PCR-based markers, Npb181, RM122, and P3, were used for the identification of the genes Xa4, xa5, and Xa7, respectively, from 56 local black glutinous rice accessions of Vietnam. Phenotypic screening of the accessions for resistance to 10 Xoo strains of North Vietnam, along with IRBB4, IRBB5, and IRBB7 as resistant controls and IR24 as a susceptible control were carried out in the 2016 Autumn season. 19 accessions containing the resistant genes were found, of these, 6 accessions carried Xa4 gene, 6 accessions carried xa5 gene, and 11 accessions carried Xa7 gene. Three accessions carried two resistance genes, viz. Nep do (Xa4 and Xa7), Pau cam (xa5 and Xa7), and Pe lon cam (Xa4 and xa5). Accessions with xa5 and Xa7 alone or with a combination of two genes (Xa4 and xa5, Xa4 and Xa7, or xa5 and Xa7) were resistantto 8-9 Xoo strains (8-9R/0M/1-2S). Accessions containing Xa4 showed resistance to 5-6 strains of Xoo (5-6R/0M/4-5S). Xoo strain No1 (HUA01043) showed the lowest virulence, infecting only 14 accessions (42R/4M/14S). Strains No3 (HUA 0020131-2), No4 (HUA202361), No5 (HUA20212), and No8 (HUA 020083) showed highest virulence, and they each infected more than 40 accessions with 19R/0M/41S, 20R/0M/40S, 16R/4M/40S, and 20R/0M/40S, respectively. These strains can even infect some accessions containing effective resistant genes (Xa4 or Xa7).