Growth and Production of Golden Shiner, Notemigonous crysoleucas, Under Different Stocking Densities and Feeding Rates

Experiments on the effects of stocking densities and feeding rates on growth and production of golden shiner were conducted under laboratory conditions. The stocking densities were 20, 28 and 36 fry per 60 gal of water. The fish in tanks with 28 fry were fed at 1, 3 and 5% feeding rates and the rest were fed at 5% feeding rate. A 5% feeding rate was found to be essential for good production. The stocking density of 20 fry (400 lb/acre production) with 5% feeding rate yielded better growth in weight and length and better production than the rest of the experimental conditions

An investigation into the potential losses of fish on the filter plates at the Hodder Water Treatment Works Stocks Reservoir

Stocks Reservoir is situated amidst the Forest of Bowland in the upper reaches of the old river valley of the Hodder. The reservoir was built in 1927 for the Fylde Water Board who primarily supplied water to Blackpool. The objective of this study is to assess the degree and likelihood of fish ingress onto the fish plates at the present and proposed stocking densities. An additional aim is to evaluate the operational implications, and if necessary suggest methods of alleviating the problem. Three spheres of study have been undertaken to achieve these objectives, these being: 1. To selectively stock the reservoir and monitor the angling club catches in order to assess the total population, relating it to fish plate losses and proposed stocking densities. 2. To monitor the fish taken from the fish plates and assess the reasons for their ingress. 3. To study the draw off tower and fish plates, and suggest ways of ameliorating or halting the loss of fish and consequent operational problems

Stress Indicator, Carcass Composition, and Meat Cholesterol of Kampung-Broiler Crossbred Chicken Treated by Different Stocking Density

This study aimed to investigate the effect of stocking density on stress indicator, carcass composition, and meat cholesterol content of kampung–broiler crossbred chicken. Anamount of 90 DOCs of crossbred kampung-broiler (KB) were placed into 9 plots sized 1x1 m2 in semi closed house that consist of 3 stocking densities 8, 10 and 12 birds m-2 and respectively 3 replicates. The chickens were fed commercial broiler feed. Approximately ± 30% roosters slaughtered for analysis of malondialdehyde, carcass quality, and meat cholesterol. Malondialdehyde, carcass composition, and meat cholesterol was completely randomized designed with different stocking densities treatments and three replicates. Data was analyzed using analysis of variance (ANOVA) and had previously been tested for requirement of variance test assumption. Data of temperature humidity index (THI) was descriptively explained. The results showed that the effect of different stocking densities on stress indicator reflected by THI value and MDA content, carcass composition (percentage of carcass and abdominal fat weight), and cholesterol level were not significant. The different of stocking densities (8, 10 and 12 birds m-2) did not affect the stress indicators reflected by THI and MDA level, carcass composition and meat cholesterol level. Kampung-broiler crossbred chicken could develop at 8, 10 or 12 birds m-2 densities since the lower of abdominal fat and meat cholesterol were resulte

Effects of socking [sic] density on ammonia excretion and the growth of Nile tilapia (Oreochromis niloticus L.)

The effects of stocking density (10, 15, 50 & 75 fish in 65L tank) and ammonia excretion on the growth of Nile tilapia, Oreochromis niloticus (12.19 ± 1.21 g) were investigated. Increasing stocking density of Nile tilapia from 15 fish/tank (2.81 g fish/L) to 75 fish/tank (14.07 g fish/L) resulted in associated increase in ammonia level (1.48 ± 0.87 mg/L to 26.44 ± 11.4 mg/L) and significantly lower growth rates. Significantly better feed conversion ratios were found for fish reared at lower (15 fish/tank) stocking densities compared to higher (75 fish/tank) stocking densities. Individual growth rates were significantly better for fish reared at a lower stocking density 15 fish/tank compared to higher stocking density 75 fish/tank and size variation (coefficient of variation in weight) were positively correlated with stocking density. Although water exchange did not have a significant effect on the growth of Nile tilapia for fish stocked at 10 fish/tank (1.88 g fish/L) and 50 fish/tank (9.38 g fish/L), however, the fish in the higher stocking density (9.38 g fish/L) groups and without water exchange, significantly changed the coloration of their bodies (silver to black) which may be due to the lower oxygen levels combined with higher ammonia levels. Ammonia level increased with increasing stocking density and without water exchange. In this study, it may be suggested that when fish reared at higher stocking densities then water exchange must be taken in to consideration so as to help avoid environmental and physiological stress to the fish

Effects of Temperature and Crowding on the Pathogenicity of Edwardsiella ictaluri in Channel Catfish (Ictalurus punctatus)

Channel catfish were injected with Edwardsiella ictaluri and stocked at increasing temperatures and densities. Bacteriological examination of kidney, liver and spleen revealed the greatest numbers of organisms in fish from the highest temperature and stocking density tested. Survival time was the shortest for fish held at the highest temperature and stocking density. Increased temperature and crowding were directly proportional to the number of organisms recovered from the organs and inversely proportional to fish survival time

Economic impact of decreasing stocking densities in broiler rabbit production based on Belgian farm data

[EN] Stocking density is a prominent issue in public debates on farm animal welfare. Public perceptions and economic impact of reduced stocking density should be considered, along with effects on animal performances and welfare. In this paper, experimental data and accountancy data based on 15 Belgian farms were combined to calculate the financial impact of different stocking densities on broiler rabbit farm profitability. Using the partial budget technique, only those elements that change with stocking density were taken into account. From the experiment, feed conversion and feed intake were found to increase slightly though significantly with decreasing stocking density, although only 5% and 6% of the variation, respectively, were explained by stocking density. However, reducing stocking density implies a recalculation of all costs in a reduced number of broiler rabbits, which has a negative impact on farm profitability. Reducing stocking density from the standard situation of 15 rabbits per m² to 10 rabbits per m² reduced added value by 22 euros per doe. In general, farm income was low and amounted to only 28.10 euros per doe during 2006-2008 for the reference situation of 15 rabbits per m². Below a density of 9 rabbits/m², a negative farm income was calculated. Sensitivity analysis showed that rabbit meat price has a stronger influence on the added value at a given density than rabbit feed price.This research is funded by the Agency for Innovation by Science and Technology in Flanders (IWT Vlaanderen), Brussels, Belgium. We gratefully acknowledge the Flemish Association of Poultry and Rabbit Breeders, and especially Ilka Hertogs for their willingness to provide the used accountancy data.132Verspecht, A.; Maertens, L.; Vanhonacker, F.; Tuyttens, F.; Van Huylenbroeck, G.; Verbeke, W. (2011). Economic impact of decreasing stocking densities in broiler rabbit production based on Belgian farm data. World Rabbit Science. 19(3). doi:10.4995/wrs.2011.849SWORD12319

On diversity effects of alternative agricultural policy reforms in Finland: An agricultural sector modelling approach

The aim of this study is to predict diversity effects of agricultural policy reforms in which direct aid payments are disconnected from production, and compare the outcomes with effects of such a policy in which CAP support is coupled. The study employs the dynamic regional sector model of Finnish agriculture. The sector model predicts regional land use, stocking densities, pesticide application areas, and nutrient balances

Effect of stocking density on the production of common carp (Cyprinus carpio Lin.) in cages at Kaptai lake, Bangladesh

Growth, survival and food conversion ratio (FCR) of Cyprinus carpio in cages at different stocking density were studied in Kaptai lake. Fingerlings of common carp (12.47 ± 4.29 g) were stocked at 25/m2 , 50/m2 and 75/m2 each with replication in six floating net cages each of Sm x Sm x 4m and reared for 240 days. The growth rate was inversely related to the stocking density with the mean weights of 325.5 ± 11.74 g, 268.99± 8.44 g and 167.0 ± 11.66 g at low, medium and high densities, respectively. At harvest, standing crop biomass averaged 7 .82, 12.83 and 11.58 kg with the survival of 98.9%, 97.6% and 94.4% and food conversion ratios of 4.51, 3.82 and 4.21 for the above three densities, respectively. Weight gain and production at density 25 fish/m 2 were significantly different (p< 0.01) from other two densities. Water quality was not affected in the cages having different stocking densities