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A Preliminary Study on the Effect of Replacing Part of Fishmeal by Brewer's Yeast in Feeding Taiwan Loach
Get PDFIn this experiment, brewer's yeast was used to replace part of the fish meal in the feed to formulate a high-fat and low-protein feed for Taiwan loach. The effects of brewer's yeast on the growth performance, muscle quality, hepatopancreas and pancreas carnitine content, intestinal flora, immunity, and antioxidant ability of Taiwan loach were preliminarily investigated. In experiment 1, 600 Taiwan loaches were randomly divided into 4 groups, and 1% (group A), 4% (group B), 8% (group C), and 12% (group D) of brewer's yeast was substituted for an equal amount of fishmeal in the basal diets. The loaches in each group were fed for 60 d. In experiment 2, 60 Taiwan loaches were selected and randomly divided into a control group (Group E) and a test group (Group F). The loaches were fed the basal diet and the high-fat and low-protein diet supplemented with 8% fishmeal, replaced by brewer's yeast. The experiment lasted for 60 days, and the growth performance, hepatopancreas carnitine content, muscle quality, intestinal flora, plasma antioxidant, and immune capacity indices of loaches in each group were determined. The results were as follows: the weight gain rate and specific growth rate were significantly higher in group C than those in groups A, B, and D (P ); the intestinal length ratio, muscle hardness, hepatopancreatic carnitine content, plasma superoxide dismutase activity, catalase activity, total antioxidant capacity, and lysozyme activity were significantly greater in group F than those in group E (P ); the Lactobacillus and Bifidobacterium counts in Group F were considerably higher than those in Group E (P ), and the Salmonella counts in Group F was significantly lower than that in Group E (P ); the survival rate, weight gain rate, bait coefficient, muscle crude protein, crude fat, viscosity, elasticity, cohesion, chewability, and restorative capacity were not significantly different between Group F and Group E (P > 0.05). The above results showed that adding 8% brewer's yeast to feed Taiwan loach instead of fish meal could enhance its hepatopancreatic carnitine synthesis, optimize the intestinal flora, improve the body's immune and antioxidant ability, and have a certain promotional effect on the intestinal development and muscle quality improvement
Evaluation of earthworm meal (<em>Eudrilus eugeniae</em>) as fish meal replacement in juvenile Mangrove Crab (<em>Scylla serrata</em>) diet
No full textTwo feeding trials were conducted to evaluate the performance of the earthworm (Eudrilus eugeniae) meal (vermimeal) as a replacement for fish meal in the diet of juvenile mangrove crab (Scylla serrata) in terms of growth, feed efficiency, intermolt duration, carapace width increment, molting success, survival, and incidence of cannibalism. Four experimental diets were formulated with 0, 25, 50, and 75% fish meal protein replaced with earthworm meal protein, designated as D0, D25, D50, and D75, respectively. In the first feeding trial, the experimental diets were fed to crablets with an initial average weight of 0.09±0.007g. Each replicate comprised ten (10) crablets individually stocked in 750ml-capacity plastic containers randomly distributed in a static water bath. Final weight gain, feed efficiency and survival were measured after the 5^th^ molt. In the second feeding trial, 150 crablets with an average weight of 0.07±0.002g were stocked at 30 crablets each in five (5) replicate tanks. Survival and incidence of cannibalism were monitored daily until the end of the culture period of 30 days. The first study showed that the growth of mangrove crab juveniles fed the diet with up to 50% of the fish meal protein replaced by the earthworm meal protein was statistically comparable to the control group. The survival of crablets in the second feeding trial was highest in D25 (33%), followed by D50 (29%), D0 (18%), and lowest in the group fed with D75 (13%). Overall, earthworm meal (Eudrilus eugeniae) can replace as much as 50% of the fish meal protein in juvenile mangrove crab (Scylla serrata) diet without negative effects on growth, carapace width increment, feed efficiency, intermolt duration, molting success, survival, and cannibalism
Genetic population structure of the pen shell <em>Atrina pectinata</em> along the coastlines of China revealed by microsatellites
Get PDFBackground
An ecologically and economically important species in East Asia, the natural resources of pen shell Atrina pectinate have suffered severe population declines due to habitat destruction, pollution, and overfishing. Assessing genetic diversity and population structure is the basis for establishing conservation programs for A. pectinate.
Results Our data indicated that high genetic diversity was found in all six populations, with mean allelic richness (Ar) ranging from 8.255 to 9.734, mean observed heterozygosity (Ho) from 0.574 to 0.680, and mean expected heterozygosity (He) from 0.620 to 0.691. The five A. pectinate populations were divided into two clusters. This clustering result was partly consistent with their geographical origin; the RZ population did not cluster with the northern populations (DL, CD), suggesting that there is no genetic divergence and geographical differentiation between the North China Sea (CD, DL, and RZ) and the Southeast China Sea (HK and ST).
Conclusion
Our results show no significant genetic differentiation between samples from the North China Sea and the Southeast China Sea. High dispersal potential of larvae by passive drift with ocean currents may explain the lack of genetic differentiation between samples. The results suggest a weak level of genetic structure in A. pectinate with a long planktonic larval stage.</p
Characteristics of surface flow field and substrate in the spawning ground of <em>Schizothorax grahami</em>
Get PDFThe Spawning ground is a crucial habitat for fish, and the physical characteristics of the habitat are important for fish life history. In this paper, Large-Scale Particle Image Velocimetry (LSPIV) was used to measure the surface flow field and the substrate (particle size and mineral composition) in the spawning ground of Schizothorax grahami. Based on the literature and consideration of experimental feasibility, two spawning grounds in the source of the Chishui River were selected—Erlongqiangbao (located in the mainstream) and Bamaoba (located in the tributary), two and three cross sections of each river section were analyzed respectively. The results show that Erlongqiangbao first flows in the direction of "southeast-northwest" and then "southwest—northeast" after crossing the bridge; the maximum velocity of the reach is 3.374m/s. The size of the substrate is mainly less than 1mm in the upstream section of Erlongqiangbao, both 25-50mm in the middle and downstream, and the substrate type mainly is quartz and calcite; Gushangtian flows in the direction of "southwest-northeast," the maximum velocity of the reach is 1.537m/s, the size of the substrate is mainly greater than 50mm in the upstream, and 25-50mm in the middle and downstream, the substrate type mainly is quartz, calcite, and dolomite. The mineral compositions of the two spawning sites were analyzed by principal component analysis. Quartz and anorthose are more than 1 in composite scores, respectively ranked first and second, indicating that they play a dominant role in the mineral composition. This study could provide basic data and ideas for restoring S. grahami spawning ground
Growth, survival and food utilization efficiency of longfin batfish (<em>Platax teira</em> Forsskål, 1775) larvae reared under different salinity levels
Get PDFSalinity is crucial in fish larval rearing. In longfin batfish (Platax teira), little research has been conducted regarding the specific effects of salinity on growth, survival, deformity, and food utilization efficiency. This study aimed to determine the optimal salinity level for larval rearing of the longfin batfish by testing five different salinity levels (10, 15, 20, 25, and 30‰). Larvae of 1.5 cm in length and 0.2 g/fish in weight were stocked in cylindrical fiberglass tanks (300 L) at a density of 1 fish/L. The fish were fed to meet their dietary requirement and divided into four daily feedings. Each treatment was replicated three times over a 28-day period of rearing. The results revealed that salinity significantly influenced the growth (length, weight, biomass), and food utilization efficiency of the longfin batfish larvae. Overall, larvae reared at salinity levels of 15-20‰ exhibited superior performance compared to those exposed to salinity levels of 10, 25, and 30‰. However, salinity did not affect the coefficient of variation, survival, and deformity. From these findings, it is recommended to rear longfin batfish larvae at a salinity of 15-20‰ to achieve optimal growth and food utilization efficiency. This study provides valuable insights for longfin batfish larval rearing guidance, contributing to the aquaculture development of this economically valuable species
Waimanalo, Photo Contour Map, 1959, Index
No full textIndex to the 12-sheet set of photo contour maps of Waimanalo 1959
Isolation of <em>Lactobacillus plantarum</em> CMT1 from shrimp intestine and its effects on growth and survival of the whiteleg shrimp, <em>Litopeneaus vannamei</em>
Get PDFProbiotics are widely applied in aquaculture, which can improve the growth, survival and health of aquatic animals. The aim of this study was to isolate and evaluate a Lactobacillus strain from the intestine of healthy whiteleg shrimp, Litopenaeus vannamei. A total of 20 Lactobacillus isolates showed rod-shaped morphology, gram-positive, non-motile, non-spore forming, and catalase and oxidase negative. Among the isolates, strain CMT1 exhibited the highest antibacterial activity against Vibrio parahaemolyticus and extracellular enzyme activity, which was selected and identified as Lactobacillus plantarum CMT1 based on 16S rDNA gene sequencing. This strain was also chosen to evaluate its effects on growth and survival of the whiteleg shrimp as a feed supplement. Four different diets were prepared, including the control (a commercial diet without L. plantarum CMT1) and three different concentrations of L. plantarum CMT1, viz. T1 (10^6 CFU kg diet^-1), T2 (10^7 CFU kg diet^-1), and T3 (10^8 CFU kg diet^-1). After a 56-day feeding trial, the growth parameters in the T3 group had the highest values and showed a significant difference compared to the other groups. The survival rates of shrimp fed T2 and T3 diets were significantly higher than those in the control diet (p Lactobacillus counts in T2 and T3 groups increased significantly from day 28, which indicated that L. plantarum CMT1 could sustain its population in the intestine of shrimp. However, the total Vibrio sp. count in the T2 and T3 groups was significantly lower than that in the control group (p L. plantarum CMT1 could be used as a potential probiotic for shrimp aquaculture, and the recommended level of the probiotic strain CMT1 is 10^8 CFU kg diet^-1
Morphological variation of endemic <em>Gymnocypris chilianensis</em> (Cyprinidae) collected from three inland water systems in Qilian Mountains, China
Get PDFTo explore the morphological differences among different geographic populations of Gymnocypris chilianensis, 29 measurable traits and 13 landmarks on 191 individuals of 10 geographic populations were collected from three different inland water systems, i.e., Shiyang River, Heihe River, and Shule River, in Qilian Mountains, China. Multivariate statistical methods were used to compare morphological differences among the populations, such as principal component analysis, cluster analysis, discriminant analysis, and visual analysis of landmark data. The results showed that: (1) There were significant morphological differences between groups of G. chilianensis. The Shiyang River basin differs significantly from populations in the other two basins. (2) The inter-population differences were mainly reflected in the length of the trunk and tail, and the difference between trunk and caudal fin had the most obvious characteristics, proving the tail being the main direction of variation. This research provides an effective theoretical basis for the fine management and accurate protection of G. chilianensis germplasm resources
Exploring Multiple Paths to Improve Fishery Financial Performance from a Configuration Perspective: A Study Based on the fsQCA Method
Get PDFImproving the financial performance of fishery enterprises is an inevitable choice to promote the development of fishery economy. In this paper, 102 observation samples are selected, and the necessary and sufficient conditions for high financial performance of fishery listed companies are analyzed by using collocation perspective and qualitative comparative analysis (QCA). Research has found that the formation of high financial performance is a complex causal relationship with multiple concurrent factors, which is the result of the combined effect of multiple conditions, and the effect of each condition is not equal; Moreover, there is no unique optimal model, and 6 different conditional configurations (paths or models) can achieve the same results. The conclusion of this study is helpful to enriching the research on the factors affecting the financial performance of fishery enterprises from the perspective of system integration, and is of great theoretical and practical significance to reveal the factor combination mode produced by the research tendency of fishery enterprise 'performance