Increasing Stocking Density Research Articles

An in-pond tank culture system for high-intensive fish production: Effect of stocking density on growth of grass carp (Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream(Megalobrama amblycephala Yih, 1955)

Pond partitioned aquaculture system is developed in recent years, and it contributes to increasing yield and lowering land occupation. Based on the concept of partitioned aquaculture system, a new in-pond tank culture system (IPTCS) was constructed in this study. This system consists of culture tank, capture and aeration module, waste collection module, and vertical flow constructed wetland (VFCW), and the effective rearing area takes up about 10.05% of the pond area. In IPTCS, grass carp ( Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream ( Megalobrama amblycephala Yih, 1955) were reared at high and low stocking densities for 120 days. The initial density of grass carp in the high and low density groups was 15 kg m −3 and 7.5 kg m −3 , respectively, and that of blunt snout bream were 10 kg m −3 and 5 kg m −3 . During the experiment, the aeration module worked 6 h / day, and the waste collection module worked 5 min / day. The results showed that high stocking density had a negative impact on the growth performance and muscle quality of grass carp and blunt snout bream, and that the water quality in the culture tank gradually was deteriorated with the increasing stocking density. The economic benefits of different stocking densities in this system were investigated in this study, and grass carp high-density rearing failed to generate high benefits, but blunt snout bream high-density rearing leads to a higher income. The feasibility and rearing effect of the in-pond culture tank system were preliminarily confirmed. • A new type of in-pond tank culture system (IPTCS) was constructed. • The economic benefit of theIPTCS was analyzed.

Effect of stocking density on growth performance, digestive enzyme activity, body composition and gene expression of Asian seabass reared in recirculating aquaculture system

Stocking density is one of the critical factors that influence the production and health status of fish in aquaculture practices. In this 60-day trial, effect of different stocking densities (70, 140, 210, 280 and 350 fish/m3) on growth performance, digestive enzyme activity, body composition and gene expression of Asian seabass, Lates calcarifer, was studied using Recirculating Aquaculture System by following completely randomized design with four replications. Asian seabass (5.20 ± 0.10 g) were randomly distributed in 20 tanks, each of 500-L capacity, and fed four times a day (6:00, 12:00 18:30 and 23.00 h). The study found that growth performance and feed utilization efficiency were significantly decreased with increasing stocking density. A significantly higher survival (95.00 ± 1.25%) was recorded in the low stocking density group (70 fish/m3). On the other side, fish reared in higher stocking densities (140, 210. 280 and 350 fish/m3) displayed lower digestive enzyme activities, such as protease, amylase, lipase and cellulase. There is a significant density-dependent decrease in crude protein deposition in the fish body and the study found significantly higher protein (19.12 ± 0.10%) content in the 70 fish/m3. The relative gene expression of GH/IGF axis and myostatin (MSTN) was significantly down-regulated and up-regulated, respectively, with the increasing stocking density. Overall, the study found that the increasing stocking density produced chronic stress which negatively affected the growth performance of the fish. Therefore, the study suggests that rearing of Asian seabass at a stocking density of 70 fish/m3 in a recirculatory aquaculture system could improve the growth performance, metabolic and molecular activities of the fish.

INFLUENCE OF THE CONDITIONS OF KEEPING LAYING HENS ON THEIR PRODUCTIVITY AND EFFICIENCY OF FOOD EGG PRODUCTION

In the conditions of industrial production of poultry products, the body of hens is constantly exposed to numerous technological stressors that reduce the level of immunological reactivity of the bird's body, which leads to a decrease in its productivity and significant economic losses. One of these stressors is the increased density of hens. At the same time, increased stocking density is a resourcesaving method in egg production, which is often used to obtain more eggs from available production areas. Therefore, the goal was to study the influence of the density of keeping hens of an industrial herd in modern 12-tier cage batteries on their productivity and the efficiency of production of food eggs. For this, hens were kept in cages of multi-tiered batteries for 44 weeks at different densities, namely 13.3 birds m2, which corresponded to European standards, 24.0 birds/m2 – according to Ukrainian standards, and with increasing overcrowding – 25.3 and 26.7 birds m2 It was found that increasing the density of keeping hens to 25.3 birds /m2 leads to a certain decrease in the viability and productivity of hens and at the same time makes it possible to obtain an additional larger number of eggs per 1 m2 of the poultry house area during the 44-week egg-laying period. In particular, in the experiment, an additional 4.5 million eggs were obtained from each poultry house (1,714 eggs from 1 m2 of its area) compared to domestic norms at a higher level of the European coefficient of efficiency of their production, and 40 million eggs (15,138 eggs from 1 m2 of its area), compared to European norms at the same level of the European coefficient of efficiency of their production. Whereas overdensification up to 26.7 birds/m2 is impractical, as it causes the development of stress in laying hens, the consequences of which are a decrease in survival by 8.9-9.0% and laying by 4.0-5.8%, which leads to a decrease level of the European coefficient of efficiency of egg production by 1.0 units.

ẢNH HƯỞNG ĐỒNG THỜI CỦA HÌNH THỨC VÀ MẬT ĐỘ NUÔI TỚI TỈ LỆ SỐNG, SINH TRƯỞNG, NĂNG SUẤT VÀ HIỆU QUẢ KINH TẾ CỦA TU HÀI (Lutraria rhynchaena) TẠI VÂN ĐỒN, TỈNH QUẢNG NINH

This study was conducted to evaluate the effects of farming methods and density on the survival rate, growth, yeild and economic efficency of commercial otter clam in the sea waters of Van Don, Quang Ninh. The otter clams with an initial length of 18,36 mm and an average body weight of 4,12 g were used in this study. Two farming methods were arranged: cage culture (basket) hanging on the raft (including experiments TN1, TN2, TN3 and TN4) and cage culture placed on tidal flats (including experiments TN5, TN6, TN7 and TN8). For each culture, there were 4 formulas for stocking density of 25 individuals\cage (100 individuals\m2) (TN1, TN5), 35 individuals\cage (140 individuals\m2) (TN2, TN6); 45 individuals\cage (180 individuals\m2) (TN3, TN7); and 55 individuals\cage (220 individuals\m2) (TN4, TN8). Each treatment was triplicate and lasted for 12 months, the results showed that the density and farming methods had different effects on growth, survival rate and yield of commercial otter clam. The weight of the commercial otter clam ranged from 28,76 to 41,74 g\individual, the length varied from 51,17 to 72,69 mm\individual, and the survival rate fluctuated from 57,4 to 78,3%. The highest growth was recorded in the TN1 with density of 25 individuals\cage, the difference between treatments was statistically significant (p≤ 0.05). The average yield of commercial otter clam increased with the increase of stocking density, ranging from 21,7 to 38,3 tons\ha, the difference was statistically significant (p≤ 0,05). However, economic accounting showed that the economic efficiency was highest in TN2, the ottet clams were arranged in the cage hanging on rafts and stocking at a density of 35 individuals\cage (140 individuals\m2). In this experiment, the average growth in weight was 38,91 g\individual and in length was 68,47 mm\individual, the survival rate was 76,4%, and the yield was 32,9 tons\ha the economic profit reached 0,883 billion of Vietnam Dong and the profit rate reached 28,1, respectively. Based on these research results, it could be recommended to farmers to stock the otter clam with a density of 35 individuals\cage.

Optimization of stocking density for mono-sex Nile tilapia (Oreochromis niloticus) production in riverine cage culture in Bangladesh

Determining a suitable stocking density of fish for an ambient condition is very important for economic benefit in cage aquaculture, which is not yet tested for many species in Sylhet district of Bangladesh. Therefore, current research was conducted in order to explore the effect of various stocking densities on growth and production performances of mono-sex Nile tilapia cage aquaculture in an open running water body, the Gurukchi River. Considering maximizing economic benefit, it is the first instance of such research in the Sylhet district of Bangladesh. In the three treatments (T1, T2, and T3), fingerlings were stocked at 40, 60 and 80 fish/m3, respectively with initial weights of 39.51 ± 0.91, 39.61 ± 0.71 and 38.54 ± 0.57g, respectively. Fish were fed with commercial floating pellet feed at 8-4% of their body weight. The results showed that growth performance of Nile tilapia significantly decreased with increasing stocking density. The mean total yields were 13.25 ± 0.48, 18.43 ± 0.88 and 22.76 ± 0.63 kg/m3 in T1, T2 and T3, respectively, which showed significant variations (p < 0.05) among treatments. The benefit-cost ratio analysis revealed that T1 (1.512 ± 0.022) and T2 (1.499 ± 0.063) were significantly (p < 0.05) higher than T3 (1.191 ± 0.071), with no significant differences observed between T1 and T2. Notably, a significantly higher (p < 0.05) net profit was observed in T2 than in T1 and T3. Overall, 60 fish/m3 stocking density was the best stocking density for commercial cage aquaculture of tilapia in a riverine environment of the north-eastern Bangladesh.

TECHNOLOGICAL AND ECONOMIC ASPECTS OF INDUSTRIAL PRODUCTION OF BROILER MEAT

The issues of development and implementation of resource-saving technologies in broiler poultry farming have a complex purposefulness and their solution must be scientifically substantiated and cost-effective. The productive qualities of meat chickens and broiler chickens of the productive crosses are significantly influenced by many factors that make up the conditions of keeping and feeding. The use of Apex and Emicidin preparations both separately and in combination with each other when rearing chickens of the broiler parent flock of the Ross 308 cross had a positive effect on their productivity and the quality of hatching eggs obtained at the end of the productive period, at the age of 52 weeks. Egg production per initial hen exceeded that in the control group by 2.6% in experimental group 1 (Emicidin), by 3.2% in experimental group 2 (Apex 3010), and by 5.8% in experimental group 3 (combined use of Emicidin and Apex 3010). The determined zootechnical indicators showed high efficiency of the use of the GerbaStor preparation for the floor rearing of broiler chickens of the Ross-308 cross in conditions of increased stocking density in winter. The difference in the productivity index was 18 units, and in meat yield from 1 m² of floor, it was 1.37 kg (3.8%) in favor of the broilers of the experimental group 2, who received GerbaStor. The profitability of the production and sale of meat of broilers grown under an increased stocking density using the GerbaStor preparation was 3.95% higher than that of broilers in the control group.

Effect of stocking density and algal concentration on production parameters of calanoid copepod Acartia bilobata

The present study investigated the effect of initial adult stocking densities and algal concentrations on production parameters of calanoid copepod, Acartia bilobata. Experiments were in triplicate with seven initial stocking densities (125, 250, 500, 1000, 2000, 4000, and 8000 adult copepods L−1) fed at three different concentrations (0.5, 1 and 5 ×105 cells mL−1) of Isochrysis galbana. Various production parameters; egg and nauplii production, egg hatching success, adult survival, and sex ratio were estimated. Individual egg production (IEP) increased from day one to five in all the groups irrespective of stocking densities and algal concentrations. IEP decreased significantly (p < 0.05) on day 1 from 9.61 ± 0.79–0.17 ± 0.05 eggs female−1day−1, and on day 5 from 13.44 ± 2.94–2.99 ± 0.58 eggs female−1day−1 with increase in stocking density from 125 to 8000 adult copepods L−1 respectively; however, an increase was noted as algal concentration increased. Total accumulated egg production increased upto the density of 1000 adults L−1, with 33945.02 ± 1556.43 eggs L−1 at highest algal concentration, and thereafter declined at higher densities. Synergistic effect of stocking density and algal concentration significantly impacted 16 and 24 h hatching success. Copepod adult survival decreased significantly from 71% to 78% (125 adult copepods L−1) to 2–10% (8000 adult copepods L−1) with increase in stocking density. It is concluded that moderate stocking density of 1000 adults L−1 with highest algal concentration (5 × 105 cells mL−1) is optimum for higher reproductive performance (egg production and hatching success) of A. bilobata. Present study provides baseline information for A. bilobata commercial mass production for use in hatcheries.

Characterization and expression analysis of heat shock protein 90β from golden pompano (Trachinotus ovatus, Linnaeus 1758) in responses to stock density stress and Cryptocaryon irritans infection

Heat shock protein 90 family, a class highly conserved protein and important molecular chaperone and its plays a role in enhancing animal adaptability to environmental stress and improving immunity. In this study, a full-length HSP90β cDNA (ToHSP90β) sequence was identified from Trachinotus ovatus. The cDNA of ToHSP90β was 2648 base-pairs (bp) long and contained a 5′-terminal untranslated region of 130 bp, a 3′-terminal untranslated region of 334 bp, and the open reading frame length 2184 bp, which can encode 728 amino acids. The ToHSP90β has a heat shock protein 90 family signature. The ToHSP90β amino acid sequence has high homology with other fish HSP90β amino acids (92.5-99.17%) and contains five conserved signal regions and a structural feature of the cytoplasmic HSP90 family. Phylogenetic tree analysis indicated that ToHSP90β was most closely related to Seriola dumerili HSP90β. Tissues expression analysis showed that the ToHSP90β was expressed in all nine tissues of T. ovatus, and its expression was the highest in the intestine. The stocking density significantly affected the expression of ToHSP90β in the kidney and brain tissues, and its expression levels increased significantly with increasing stocking densities, indicating that it plays an important regulatory role in the process of T. ovatus’ chronic stress response. After Cryptocaryon irritans infection, the mRNA expression of ToHSP90β was significantly increased in liver and kidney tissues, indicating that ToHSP90β would be involved in the immune regulatory response. This study was the first to analyze the expression pattern of HSP90β mRNA in T. ovatus tissues and their expression responses to stocking density stress and C. irritans infection. To provide a theoretical basis for further study of the function of fish HSP90 and its physiological mechanism in environmental stress and parasite infection.

Estimates of stocking density of female geese in different growth stages

A high stocking density can have a negative effect on growth performance, walking ability, and antioxidant capacity of poultry. In geese production, multiple-phase feeding strategy is generally adopted when considering the long raise period for geese. However, the corresponding density parameters are lacking in different growth stages. The aim of this study was to estimate the optimum stocking density of geese from 14 to 28 d of age and 28 to 49 d of age and investigate the effects of stocking density on antioxidant capacity of geese from 28 to 49 d of age. Two trials were used in this study. In experiment 1, a total of 432, 14 d of age female White Sichuan geese were allocated randomly to 6 treatments with 6 replicate pens per treatment according to the stocking densities of 4.67, 6.00, 7.33, 8.67, 10.00, and 11.33 birds/m2, respectively. In experiment 2, a total of 324, 28 d of age female White Sichuan geese were allocated randomly to 6 treatments with 6 replicate pens per treatment according to the stocking densities of 2.50, 3.75, 5.00, 6.25, 7.50, and 8.75 birds/m2, respectively. With the stocking density increasing, body weight and weight gain decreased linearly or quadratically in experiment 1 (P < 0.05), feed intake decreased quadratically (P < 0.05), and feed/gain ratio (F/G) increased (P < 0.05). In experiment 2, as the stocking density increased, the body weight and weight gain decreased linearly (P < 0.05), while F/G increased linearly (P < 0.05). In addition, the increasing stocking density resulted in that the serum total antioxidant capacity (T-AOC) level and activity of superoxide dismutase (SOD) both decreased linearly (P < 0.05). According to linear broken-line regression, the upper critical stocking density of geese from 14 to 28 d of age for weight gain was 6.15 birds/m2 (or 8.34 kg of actually achieved BW/m2) and it was 4.83 birds/m2 (or 11.4 kg of actually achieved BW/m2) for F/G of geese from 28 to 49 d of age.

Effects of stocking density on a typical crab-clam polyculture system: Behavioral mechanisms of predation and competition in swimming crab (Portunus trituberculatus)

Stocking density determines the performance of polyculture. However, the underlying mechanisms of how density affects the behavior of aquaculture animal are still unclear, especially the predation and competition. Here we selected a typical polyculture system containing predator swimming crabs (Portunus trituberculatus) and prey Manila clams (Ruditapes philippinarum), and examined the influence of stocking density on crab predation, competition, and their interactions. Specifically, we calculated the predation rate, and quantified the foraging behavior and encounter behavior between crabs. Results show that, with increasing stocking density, the predation rate significantly decreased as a result of aggressive interactions between crabs (e.g., fighting and threatening). Increased crab density promoted their competition, which was manifested as an increase in the proportion of time spent on aggression. However, the probability of aggressive behavior upon encounter was reduced to avoid time loss and the risk of injury during aggression. Nevertheless, the prolonged aggressive behavior negatively affected the foraging efficiency, as indicated by an increase in the proportion of handling time and a decrease in the probability of consumption upon capture. While the crabs attempted to compensate for the reduced foraging efficiency by significantly increasing the probability of capture upon encounter, the impacts of aggressive interactions outweighed their coping capacity, rendering a reduction in observed predation rates. The revealing of behavioral mechanisms not only provides an improved understanding of how the stocking density affects the behavior of crabs, but also helps to optimize the management of crab-clam polyculture.

Effect of stocking density on performance, infection by Eimeria spp., intestinal lesions and foot pad injuries in broilers with outdoor access under tropical conditions

ABSTRACT 1. The study was carried out to evaluate the effect of stocking density on performance, litter moisture, Eimeria oocyst shedding, intestinal and foot lesions in broilers. 2. A total of 192 1-d-old male Cobb broilers were distributed with three different stocking densities (6, 8 or 10 chickens/m2) with outdoor access and eight replicates in a completely randomised design over two periods. Productive parameters were measured from 3 to 7 weeks of age. 3. Oocyst counts (OPG) in both excreta and litter were performed at 3, 4 and 5 weeks of age. Intestinal and foot pad lesions were evaluated at 7 weeks old. The stocking density of 6 birds/m2 had the highest body weights (P < 0.05) (2129 ± 37.67, 2759 ± 50.82 and 3167 ± 75.64 g at weeks 5, 6 and 7 of age, respectively). 4. Feed intake decreased with increasing stocking density at week 3 (r = −0.57), 4 (r = −0.48), 5 (r = −0.84), 6 (r = −0.68) and 7 (r = −0.65) of age (P < 0.05). Birds with stocking densities of 8 and 10/m2 consumed, respectively, up to 11% and 19.5% less feed than the lower stocking density groups. 5. Stocking density affected (P < 0.05) feed conversion (1.61, 1.49 and 1.46) and litter moisture (40.88, 52.60 and 56.19%) at 3 weeks of age. Neither carcase yield nor mortality was different between densities (P > 0.05). Likewise, there was no effect of stocking density on OPG neither in excreta nor in litter, intestinal lesions, or foot pad and hock injuries (P > 0.05). 6. In conclusion, the higher stocking density decreased both the feed intake and the live weight in broilers, but there were no effects in the number of Eimeria OPG in excreta or litter, neither intestinal lesions nor in foot pad injuries.

Stocking density matters in open water cage culture: Influence on growth, digestive enzymes, haemato-immuno and stress responses of Puntius sarana (Ham, 1822)

A 90 days trial was carried out to investigate the impact of stocking density on growth performances and the health status of Puntius sarana in inland open water cages (Salia Dam of Odisha, India). The fishes of mean body weight 32.04 ± 1.25 g were stocked @ three stocking densities (SD) i.e., 10 m−3 (SD10), 20 m−3 (SD20), and 30 m−3 (SD30) and fed with commercial feed of 28% protein and 4% fat. The growth, in terms of weight gain, specific growth rate, absolute growth rate, percentage survival, protein efficiency ratio, and feed conversion efficiency was significantly decreased (P < 0.05) with increment in stocking density, however the lowest feed conversion ratio (FCR) was obtained in SD10 (1.68 ± 0.02). At the end of the experiment, a significant increase in red blood cells, haemoglobin, haematocrit, and platelets level was found in SD30, while white blood cells were showed a reverse trend. The concentration of superoxide dismutase, catalase, serum glucose, serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and cortisol were increased significantly in SD30. On contrary, the level of serum triiodothyronine and thyroxine decreased with an increase in stocking density. The higher stocking density negatively affected the amylase activity without any adverse impact on protease and lipase. The cluster analysis revealed that SD20 and SD30 came under the same dendrogram while SD10 formed a separate one. The outcome of PCA (Principal Component Analysis) revealed that increased levels of SGPT, SGOT, glucose, and cortisol negatively influenced the growth attributes. Stocking density up to 20 fingerlings m−3 of P. sarana in inland open water cages performed ideally in terms of growth and health status of fish.

Impacts of tea tree or lemongrass essential oils supplementation on growth, immunity, carcass traits, and blood biochemical parameters of broilers reared under different stocking densities

The effects of tea tree essential oil (TTEO) and lemongrass essential oil (LGEO) with different stocking densities on the growth performance, biochemical markers, antioxidants, and immunity state of broiler chickens were studied. Birds were housed at stocking densities of 25, 30, 35, and 40 kg/m2. The treatments were, basal diet without any supplementation, the second and third groups were supplemented with 300 mg TTEO/kg feed, and 300 mg LGEO/kg feed, respectively. Results revealed that increasing stocking density from 25 to 40 kg/m2 significantly reduced body weight and daily weight gain at different ages. The phagocytic index and activity were significantly higher under the lower stocking density (25 kg/m2). Serum amyloid A (SAA), serum or liver transferrin (TRF), or C-reactive protein (CRP) were significant decreased when decreasing stocking density. Increasing stocking density from 25 to 40 kg/m2 resulted in a significant increase in the serum urea, creatinine, uric acid, lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and catalase (CAT) levels. However, there was a significant reduction in antioxidant enzyme activity, including glutathione peroxidase (GPx) and superoxide dismutase (SOD), as stocking density increased. The supplementation of TTEO produced significantly higher body weight and daily weight gain followed by LGEO. Additionally, the mortality rates were reduced in TTEO (27.4%) and LGEO (25%) groups. TTEO or LGEO supplementation significantly improved meat constituents and cellular immunity and reduced serum total lipids, serum and meat cholesterol, and triglycerides, SAA, TRF, and CRP. For all these measured parameters, superior results were obtained when TTEO was used compared to LGEO. TTEO or LGEO supplementation also significantly reduced serum urea, creatinine, uric acid, and the enzymatic activities of LDH, ALT, AST, MDA, and CAT (but not GPx and SOD) in comparison to the control treatment. Overall, our results showed the superiority of TTEO over LGEO as a feed supplement in broiler diets. In conclusion, TTEO treatment offers a better solution for raising broiler chickens in high stocking density.

Evaluating growth, production and economics of a new candidate species Labeo bata in cages: A regional model for table fish production in floodplain wetlands of North East India

Indian minor carp Labeo bata fingerlings were reared in square shaped cages at different numbers to evaluate the effect of stocking density on growth, production and economics. Fifteen cages (5 × 5 × 2 m each) were installed in deeper areas (6–8 m) of Samaguri beel (a seasonally-flooded floodplain wetland) of Assam, India. The cages were stocked with L.bata (mean length 11.93 ± 0.20 cm; mean weight 13.05 ± 0.77 g) at five different stocking densities of 10 (SD10), 20 (SD20), 30 (SD30), 40 (SD40) and 50 (SD50) fingerlings m−3 in triplicates. Fish were fed with floating pellets containing 32% CP at 3–5% body weight twice-a-day for six months. Density-dependent growth was evident from the results as growth of fish decreased with increasing stocking densities; the specific growth rate of the fish at SD10, SD20, SD30, SD40 and SD50 were 1.03 ± 0.02, 0.88 ± 0.01, 0.84 ± 0.02, 0.67 ± 0.02 and 0.52 ± 0.01 with corresponding weight gain percent of 533.3 ± 13.41, 385.8 ± 10.73, 353.3 ± 14.17, 232.2 ± 8.08 and 155.9 ± 5.38, respectively. However, the highest net yield of fish was achieved at SD30 (50.8 kg cage−1), which was significantly higher than other stocking densities. Also, economic analysis demonstrated highest benefit-cost (B:C) ratio at 30 fish m−3 (1.44). Results indicated decreased fish yield at lower densities though the individual growth rate of fish was higher. On the other hand, fingerling stocking more than 30 fish m−3 was uneconomical because of lower individual growth rate. Hence, a stocking density of 30 fish m−3 could be considered as optimum for production of L.bata table fish in cages. The study generated new and critical information on species diversification in cage aquaculture for tropical floodplain wetlands.

Effect of stocking density on growth performance, feather quality, serum hormone, and intestinal development of geese from 1 to 14 days of age

This study was conducted to investigate the effect of stocking density on growth performance, feather quality, serum hormone, and intestinal development of geese from 1 to 14 d of age. A total of 450 one-day-old geese were randomly allotted to 45 battery cage (0.65 m × 0.62 m) pens according to 5 stocking densities (15, 20, 25, 30, and 35 birds/m2). The results showed that ADG and ADFI were reduced (P < 0.05) as stocking density increased from 15 to 35 birds/m2, but increasing stocking density did not influence (P > 0.05) feed conversion ratio (FCR) and body measurement traits. High stocking density significantly decreased (P < 0.05) the feather quality of back, thoracoabdominal, wing, and tail. No significant difference (P > 0.05) was found in serum concentration of adrenocorticotrophic hormone, cortisol, corticosterone, triiodothyronine, and thyroxine. The weight of cecum and intestine decreased (P < 0.05) as the stocking density increased. Increasing stocking density decreased (P < 0.05) jejunal villus height and villus height-to-crypt depth ratio, and increased (P < 0.05) jejunal crypt depth and ileal crypt depth in geese. Consequently, the high stocking density could depress the growth and impaired feather quality and intestinal development of geese. Under our experimental conditions, we recommend that the stocking density of geese from 1 to 14 d of age should not more than 20 birds/m2.

Serum clinical biochemical markers of Hy-Line W-36 laying hens under the influence of increased stocking densities in cages of multilevel batteries

Today, the organism of hens is constantly exposed to numerous technological stressors in the conditions of industrial poultry farming, the least studied of which are long-term, which can cause the development of chronic stress. One of such stressors is the increased stocking density of hens, which is also a way of saving resources in egg poultry and is often used by producers to obtain more eggs per 1 m2 of poultry area. The aim of this study was to examine the effect of overcrowding, as a factor of chronic stress development, on the body of hens of a modern high-performance cross, which is necessary to select the best ways to keep them. Four groups of hens were formed for this purpose, which were kept at different stocking densities, according to European standards, Ukrainian standards and with increasing overcrowding. In this way, the gradually increasing intensity of the technological stressor was modeled. Long-term keeping of laying hens at high stocking density did not affect the content in the serum of total protein, albumin, urea and cholesterol, which were within the physiological norm. It was found that the increase in the stocking density of hens to Ukrainian standards, compared to the European, was accompanied by an increase in the activity of lactate dehydrogenase in the serum of their blood. With an increase in stocking density above European and Ukrainian standards, namely to 25.3 birds/m2, there was an increase in the activity of three enzymes – lactate dehydrogenase, aspartate aminotransferase and gamma-glutamyltransferase. It is proved that further overcompaction of hens to 26.7 birds/m2 is accompanied by an increase in serum glucose, creatinine, as well as a decrease in the ratio of calcium and phosphorus, which was confirmed by an increase in alkaline phosphatase activity. Also, increased activity of aspartate aminotransferase, lactate dehydrogenase and gamma-glutamyltransferase was observed. Thus, the main effects of chronic stress caused by prolonged keeping of hens at high stocking densities are reflected in the biochemical parameters of their serum, namely in the increase of glucose, creatinine, enzyme activity, as well as the violation of the ratio of calcium and phosphorus.

Stocking density alters growth performance, serum biochemistry, digestive enzymes, immune response, and muscle quality of largemouth bass (Micropterus salmoides) in in-pond raceway system.

The effects of stocking density on growth performance, serum biochemistry, digestive enzymes, immune response, and muscle quality of largemouth bass (Micropterus salmoides) reared in nine in-pond raceway systems (IPRS, 22.0 m × 5.0 m × 2.0 m) were studied. M. salmoides with initial an body weight of 8.25 ± 0.51 g and body length of 6.99 ± 0.44 cm were reared at an initial stocking density of 90.91 ind./m3 (low stocking density, LSD), 113.63 ind./m3 (middle stocking density, MSD), and 136.36 ind./m3 (high stocking density, HSD) with triplication. After 300 days of culture, MSD recorded the highest final body weight, weight gain, specific growth rate, and yield, but the food conversion ratio in MSD was the lowest. The viscerosomatic index in LSD was significantly higher than other groups. The fish serum reared at HSD showed significantly lower total protein, higher total cholesterol, triglyceride, total bilirubin, glucose content, alanine transaminase, and aspartate transaminase activity. Significantly lower intestinal amylase, lipase, trypsin activities, hepatic superoxide dismutase (SOD) and catalase (CAT) activities, and higher malondialdehyde content were detected in HSD compared to others. The content of crude lipid, saturated fatty acid decreased, and total essential amino acid, delicious amino acid, and polyunsaturated fatty acid increased in muscle with stocking density increase. No significant difference was observed in muscle texture. Profitability analysis indicated the benefit-to-cost ratio varied between 1.10 and 1.68, of which MSD was significantly higher than others. The optimal stocking density for M. salmoides should be 113.63 ind./m3 in an IPRS farm.

Effects of stocking density on the performance, tibia mineralization, and the expression of hypothalamic appetite genes in broiler chickens

Abstract The current study investigated the effects of stocking density (SD) on the performance, tibia mineralization, and the hypothalamic appetite genes expression in broilers. A total of 2,800 1-d-old male broilers (Cobb 500) were distributed in a completely randomized design to 1 of 5 SD treatments with 8 replicate cages for each treatment. The SD treatments were 12.5, 15.0, 17.5, 20.0, and 22.5 birds/m2, corresponding to 50, 60, 70, 80, and 90 birds per cage (4 m2/cage), respectively. The concentration of tibia phosphorus was determined by the ammonium metavanadate colorimetric method and the mRNA abundance in different tissues was measured by the real-time quantitative PCR method. The data were analyzed by the one-way and/or two-way analysis of variance and polynomial contrasts were used to determine the effect of increasing SD. Feed intake linearly decreased (P &lt; 0.05) with increasing SD during d 1-42 production period. On d 42, body weight and tibia breaking strength were significantly lower in the groups of 17.5, 20.0 and 22.5 birds/m2 than in the groups of 12.5 and 15 birds/m2 (P &lt; 0.01). Concentrations of ash and phosphorus in the tibia of broilers linearly decreased (P &lt; 0.03) with increasing SD on d 42. The SD of 22.5 birds/m2 decreased the mRNA abundance of neuropeptide Y (NPY), NPY-receptor (NPYR) 1, and NPYR2 (P &lt; 0.05), while it increased melanocortin receptor 4 mRNA abundance (P = 0.012) in the hypothalamus of broilers as compared with the SD of 12.5 birds/m2 on d 21 and 42. The mRNA abundance of hypothalamic cocaine and amphetamine-regulated transcript (CART), corticotrophin-releasing factor (CRF), and CRF-receptor 1 (CRFR1) were higher (P &lt; 0.05) in the group of 22.5 birds/m2 than in the group of 12.5 birds/m2 on d 21. We concluded that increasing stocking density beyond 15 birds/m2 (corresponding to the 45 kg/m2 at 42 days of age) suppressed final BW and bone mineralization of broilers raised in multitier cage system. Hypothalamic NPY and CRF signaling might be involved in the anorexigenic effect of HSD.

Production performance and business analysis of clown loach Chromobotia macracanthus (Bleeker 1852) in recirculating systems with different stocking densities and water discharge

Efforts to improve the production performance of clown loach in recirculate aquaculture system can be done by increasing stocking density and water discharge. This study aimed to analyze the effect of increasing stocking density and water discharge on production performance, stress response and water quality in order to obtain the best stocking density and water discharge to obtain maximum profit in a short time. A factorial completely randomized design with two factors, i.e. the stocking density of 1, 2, and 3 fish L-1 and the water discharge of 0,05; 0,10; 0,15 L s-1 was performed. The volume of water used in each aquarium was 48 L and using a ½ inch faucet stop to regulate the water discharge from the inlet pipe. Clown fish fed Tubifex sp. with a feeding frequency of two times a day according to the treatment for 60 days. The result indicates that there was no interaction between the two factors on production performance, payback period, and R/C ratio. Stocking density has a significant effect on specific growth rate, absolute growth rate of individual weight, feeding consumption rate and R/C ratio of clown loach. Stocking density and water discharge had an interaction on the visual color of pectoral and caudal fins of clown loach. Different stocking densities with the combination of water discharge in this study resulted that the water quality were within tolerable range for clown loach so that they did not experience stress, as well as high production and business performance. It is recommended to intensify clown loach with a stocking density of 3 fish L-1 and 0,15 L s-1‑ of water discharge.

Productivity of Vannamei Shrimp Cultivation (Litopenaeus vannamei) in Intensive Ponds in Tegal City, Central Java Province

The failure of tiger shrimp (Penaeus monodon) farming could make farmers stop their cultivation activities. As an alternative, vannamei shrimp cultivation gives hope for productive, profitable, and sustainable cultivation. The development of shrimp farming in Tegal City is carried out through simple methods, intensive technology, and the use of Busmetik technology or mini-scale shrimp farming on plastic ponds. The high demand in the shrimp market continues to encourage farmers to increase their productivity by increasing stocking density. The purpose of this study is to determine the performance of vannamei shrimp cultivation which is cultivated intensively including yields, survival rate (SR), feed conversion ratio (FCR), and shrimp growth in Tegal City, Central Java Province. The research was conducted from July to October 2019. The research method used was a case study with 16 plots of ponds, and the average area of the pond was 1000 m². Based on the results of the calculation, it can be seen that the average yield is 1,603 kg per pond with a stocking density of 100 fish/m², a survival rate (SR) is 85.6%, a feed conversion ratio (FCR) is 1.41 and the shrimp growth is 0.16 grams per day. Economically, based on the Benefit-Cost Ratio (B/C ratio) of 1.46, vannamei shrimp cultivation in Tegal City is profitable so that shrimp farming can be carried out sustainably.