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21.
It is a practical approach to select candidate probiotic bacterial stains on the basis of their special traits. Production of digestive enzyme was used as a trait to select a candidate probiotic bacterial strain in this study. In order to select a bacterium with the ability to degrade both starch and protein, an ideal bacterial strain STE was isolated from marine shrimp (Litopenaeus vannamei) intestines by using multiple selective media.The selected isolate STE was identified on the basis of its morphological, physiological,and biochemical characteristics as well as molecular analyses. Results of degradation experiments confirmed the ability of the selected isolate to degrade both starch and casein. The isolate STE was aerobic, Gram-negative, rod-shaped, motile and non-spore-forming, and had catalase and oxidase activities but no glucose fermentation activity. Among the tested carbon/nitrogen sources, only Tween40, alanyl-glycine, aspartyl-glycine, and glycyl-l-glutamic acid were utilized by the isolate STE. Results of homology comparison analyses of the 16S rDNA sequences showed that the isolate STE had a high similarity to several Pseudoalteromonas species and, in the phylogenetic tree, grouped with P. ruthenica with maximum bootstrap support (100%). In conclusion, the isolate STE was characterized as a novel strain belonging to the genus Pseudoalteromonas.This study provides a further example of a probiotic bacterial strain with specific characteristics isolated from the host gastrointestinal tract. 相似文献
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A study was conducted to evaluate the effects of meat and bone meal (MBM) and poultry by-product meal (PBM) as the replacement
of fish meal in the diets on the growth performance, survival and apparent digestibility coefficients (ADC) of Litopenaeus vannamei. The basal diets were formulated with 22% fish meal and other ingredients which provided about 40% protein and 9% lipid in
the diet. The experimental diets included MBM or PBM to replace 0, 20%, 40%, 60% and 80% of total fish meal respectively.
All diets were iso-nitrogenous and isocaloric in gross terms. The results showed that there were no significant differences
(Pτ;0.05) in growth performance and ADC among the treatments fed with the diets in which 0–60% fish meal had been replaced with
MBM, while the percent weight gain (WG, %), body length gain (BLG, %) and ADC significantly decreased when the MBM was up
to 80% of the fish meal. There were no significant differences (Pτ;0.05) in growth performance and ADC among all the treatments fed with the diets in which 0–80% fish meal had been replaced
with PBM. 相似文献
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This experiment was conducted to study the characteristics of absorption of amino acids by different regions of the alimentary tract and the utilization of free amino acids in the test diets of the prawn, Penaeus oricntolis.The midgut gland is the principal site of nutrient absorption. In the foregut, the digestibility coefficient of 15 amino acids tested accounted for 52.5% of the total digestibility coefficient in the entire alimentary tract. In the midgut, the digestibility coefficient was 47.5 % of the total. There was no evidence of the hindgut assimilating amino acids.The free amino acid in the test diet, methionine, was almost absorbed before entering the midgut. Methionine could not be absorbed synchronously with other amino acids bound in the dietary protein, but it did affect the synchronization of other essential amino acids. [3H]-lysine, incorporated into the test diet, was almost totally assimilated within the midgut gland. Five and a half hours after feeding, the labelled amino acid had be 相似文献
25.
Journal of Oceanology and Limnology - To fill the blank in systematic study on the organoleptic quality of large yellow croaker Larimichthys crocea, we analyzed the organoleptic quality of the fish... 相似文献
26.
Li Xinxin Feng Xiuni Luo Kai Ma Shuoli Deng Junming Zhang Wenbing Mai Kangsen 《中国海洋湖沼学报》2020,38(6):1936-1944
Journal of Oceanology and Limnology - A 240-day feeding trial was conducted to investigate the effects of dietary vitamin C on growth performance, anti-oxidative response, and fatty acid... 相似文献
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Dietary leucine requirement for juvenile large yellow croaker, Pseudosciaena crocea Richardson 1846 (initial body weight 6.0 g ± 0.1 g) was determined using dose-response method. Six isonitogenous (crude protein
43%) and isoenergetic (19 kJ g−1) practical diets containing six levels of leucine (Diets 1–6) ranging from 1.23% to 4.80% (dry matter) were made at about
0.7% increment of leucine. Equal amino acid nitrogen was maintained by replacing leucine with glutamic acid. Triplicate groups
of 60 individuals were fed to apparent satiation by hand twice daily (05:00 and 17:30). The water temperature was 26–32°C,
salinity 26–30 and dissolved oxygen approximately 7 mg L−1 during the experimental period. Final weight (FW) of large yellow croaker initially increased with increasing level of dietary
leucine but then decreased at further higher level of leucine. The highest FW was obtained in fish fed diet with 3.30% Leucine
(Diet 4). FW of fish fed the diet with 4.80% Leucine (Diet 6) was significantly lower than those fed Diet 4. However, no significant
differences were observed between the other dietary treatments. Feed efficiency (FE) and whole body composition were independent
of dietary leucine contents (P > 0.05). The results indicated that leucine was essential for growth of juvenile large yellow croaker. On the basis of FW,
the optimum dietary leucine requirement for juvenile large yellow croaker was estimated to be 2.92% of dry matter (6.79% of
dietary protein). 相似文献
29.
A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione. 相似文献
30.
Yurong Zou Qinghui Ai Kangsen Mai Wenbing Zhang Yanjiao Zhang Wei Xu 《中国海洋大学学报(英文版)》2012,11(2):227-235
A 120-day feeding experiment was conducted to investigate the effects of partial replacement of brown fish meal (BFM) by fermented soybean meal (FSBM) in diets of Chinese soft-shelled turtle (Pelodiscus sinensis). The turtles (initial mean body weight, (115.52 ± 1.05) g) were fed with three experimental diets, in which 0%, 4.72% and 9.44% BFM protein was replaced by 0%, 3% and 6% FSBM, respectively. Results showed that the feeding rate (FR), specific growth rate (SGR) and feed efficiency ratio (FER) of turtles fed with the diet containing 3% FSBM were not significantly different from the control group (0% FSBM) (P > 0.05). However, FR, SGR and FER of turtles fed with the diet containing 6% FSBM were significantly lower than those of the control group (P < 0.05). No significant differences were observed in the activities of serum glutamic-oxalacetic transaminase and glutamicpyruvic transaminase among dietary treatments (P > 0.05). However, the uric acid concentration in turtles fed with the diet containing 3% or 6% FSBM was significantly lower than that in the control group (P < 0.05). There were no significant differences in the activities of lysozyme, alkaline phosphatase and total superoxide dismutase among dietary treatments (P > 0.05). The results suggested that FSBM could replace 4.72% BFM protein in turtle diets without exerting adverse effects on turtle growth, feed utilization and measured immune parameters. 相似文献