Lernaeid parasites prevalence in commercial freshwater fish species at various fish farms in Pakistan

Reports abound on Lernaea parasitizing the brood stock, fingerlings, and marketable-sized culturable freshwater fish species in various parts of the world. We investigated seven small-scale aquaculture farms and how the prevailing Lernaea is impacting them. Randomly seven fish farms were selected to determine the prevalence percentage of lernaeid ectoparasites. Relevant information of the fishponds to estimate the various aspects such as effects of water source and quality, feed, stocking density, treatment used, and weight and length of fish, concerned with Lernaea infestation and prevalence was gathered. The results indicated that Catla catla (F. Hamilton, 1822) showed highest prevalence (41.7%) among the seven fish species, whereas Oreochromis niloticus showed zero. Other five fish species Ctenopharyngodon idella, Cirrhinus cirrhosis, Cyprinus carpio, Labeo rohita and Hypophthalmichthys molitrix showed 13.2%, 8.1%, 7.7%, 7.4%, 0.9% prevalence, respectively. In Royal Fish Farm 84.3% lernaeid infestation was observed, while no parasite was observed in the Vicent’s Chunnian fish farm. The water source, quality, feed, fertilizers, stocking density, water temperature, and potential treatment options displayed varying tendencies among fish farms and prevalence. Depending on the weight and length, the highest prevalence (56.7%, and 66.7%) was observed in 3501-4000 g and 81-90 cm groups. The infestation rate varied in various fish body parts with the dorsal fin the most vulnerable organ and showed 2.3% overall prevalence (while 18.4% contribution within total 12.6% infestation). Out of 147 infected fish samples, 45 were extensively contaminated by Lernaea spread. In conclusion, our findings confirm that Lernaea could pose a considerable threat to marketable fish, and various treatment options should be educated to the farmers to help mitigate the spread and potential losses. Furthermore, Catla catla is more vulnerable to Lernaea infestation (41.7%), so are the fish species being cultured at higher stocking densities.

A Solution for Sustainable Utilization of Aquaculture Waste: A Comprehensive Review of Biofloc Technology and Aquamimicry

Biofloc technology (BFT) is gaining traction as a strategic aquaculture tool for boosting feed conversions, biosecurity, and wastewater recycling. The significant aspect of BFT is aquaculture with highest stocking density and minimal water exchange. It not only improves the water quality of a system by removing inorganic nitrogen from wastewater but also serves as a suitable feed supplement and probiotic source for cultured species. This technology is commonly used for shrimp and tilapia culture and can be used for both semi-intensive and intensive culture systems. Biofloc, when combined with formulated diets, forms a balanced food chain that improves growth performance. Nutrients in this system are continuously recycled and reused and form an efficient alternative system in aquaculture. In addition to the reduction in water exchange, it is also considered as a bio-security measure, since it prevents entry of disease from outside sources. Aquamimicry is an innovative concept that simulates natural estuarine conditions by developing copepods that act as supplementary nutrition especially for shrimp culture. The review highlights the process, significance, and development of BFT, its microbial interactions, nutritional value, transition from biofloc to copefloc, and concept of aquamimicry to sustainably improve aquaculture production.

First record of Trichodina heterodentata (Ciliophora: Trichodinidae) in banded knifefish Gymnotus carapo (Gymnotidae) cultured in Brazil

The aim of this study was to report the first record of Trichodina heterodentata in banded knifefish Gymnotus carapo. Banded knifefish cultivated in the municipality of Jataí, state of Goiás, in the central western region of Brazil, experienced fish mortality rates of 3-4% per tank. Macroscopic analysis found that fish had lesions on their skin and gills. Smears of the integument and gills were confectioned and air-dried at room temperature and impregnated with silver nitrate to identify the Trichodinidae species causing the lesions. The trichodinid were identified as T. heterodentata, and their characteristics were compared to those from T. heterodentata recorded from other species of host fish. It was observed that the presence of T. heterodentata was associated with inadequate fish management, low water quality, high rates of stocking density, and inadequate nutritional management.

DETERMINING THE OPTIMUM TEMPERATURE FOR GROWTH, FEED EFFICIENCY AND SURVIVAL OF DOMESTICATED INDONESIAN MAHSEER, Tor soro LARVAE

Temperature plays a pivotal role in the success of larvae production. Evaluation of the effects of different temperatures on growth, feed efficiency, and survival of domesticated Indonesian mahseer (Tor soro) larvae was carried out to determine an optimum rearing temperature. Five different temperature settings of 22°C, 24°C, 26°C, 28°C, and 30°C were used as the treatments arranged in triplicates, in indoor closed recirculating systems. The larvae were stocked in a rectangular glass tank with a stocking density of 150 larvae per tank and fed with a commercial feed (30% protein content) three times a day, about 10% per body weight over 61 days of observation. Measured parameters included the specific growth rate of total weight (SGRTW) and length (SGRTL), feed efficiency (FE), and survival rate (SR). The result showed that the treatments of different temperatures significantly affected the growth performance and feed efficiency of the larvae. The growth performance and feed efficiency of mahseer larva were much better at rearing temperature from 24°C to 28°C compared with those at 22°C and 30°C. There were no significant differences in SR in different temperatures tested. The SR was found to range from 86.44% to 100% in all treatments. Maintaining temperature ranging from 24°C to 28°C is the best rearing condition to achieve the optimum growth and feed efficiency of mahseer during the larval rearing period. The findings from this research could be set as a standard technique in larval rearing of Indonesian mahseer (Tor soro).

EXPERIMENTAL RESEARCH AND CFD MODELING OF MODULAR POULTRY BREEDING

For high-quality and simultaneous breeding of different ages of poultry a modular keeping is proposed. The heating system of the module is a panel infrared heater. It is intended for local heating of technological area. Design dimensions of the module were determined for reasons of qualitative course of technological process, namely the stocking density of poultry. Experimental studies of the temperature regime of poultry breeding area were carried out. Body temperature of the poultry was within acceptable limits, up to 41.5ºC. In addition, the surface temperature of the feathers did not exceed 29.1ºC, which fully complies with sanitary and hygienic standards. For a better representation of temperature regime in the module, CFD modeling was performed. Fields of velocities, pressures and temperatures were obtained. The air temperature near poultry in the module reached 18.6ºC, and the average velocity did not exceed 0.75m/s.

Use of hulless oats in feeding of pedigree 1+ carp as an effective method for ensuringthe physiological needs of fish

Purpose. To study the effect of addition of hulless oats during the growing period on the qualitative and quantitative indicators of replacement-brood stock of carp. Methodology. The replacement-brood stock of Lubin intra-breed type of Ukrainian scaly carp strain, which were kept in ponds of State Enterprise Experimental Fish Farm of Lviv Research Station of the Institute of Fisheries of the National Academy of Agrarian Sciences of Ukraine (IFNAASU) was used for the study. The stocking density was 1000 fish/ha. The experiment was based on four experimental groups. Carps of the first experimental group were fed during the entire growing period with a feed mixture with the addition of hulles oats in the amount of 10 %, while carps of the second group were fed with a feed with the addition of 30 % of hulless oats. The third experimental group received a feed mixture in June – July, and hulless oats in August. The control group of carp was fed with the feed mixture throughout the entire growing period. The stocking density of fish was 1000 fish/ha. Piscicultural studies were conducted in accordance with current methods. Sampling of water for chemical analysis and its processing in the laboratory was carried out according to O. Alokin according to the Standard of the Ministry of Agrarian Policy of Ukraine. Haemoglobin content was determined by the haemoglobin-cyanide method. Blood erythrocytes were counted in a Goryaev chamber. Abundance and weight of natural feeds in ponds were determined according to I.A. Kyseliov, V.I. Zhadin. Zooplankton biomass was determined using tables of individual weights of F.D. Mordukhai-Boltovskoi. Analytical processing of the material was performed using MS Excel. The criteria for the analysis of indicators were their mean (M) and mean deviation (m). Findings. Peculiarities of growth, development of carp and efficiency of feed usage with the addition of hulless oats on the background of similar satisfactory growing conditions were studied. It was found that additional feeding of carp with hulless oats at an amount of 30% was effective. In particular, its addition resulted in an increase in individual weight by 31.1% and survival rate by 2.33%. Studies of the physiological functions of the body of experimental fish during the growing period after adding the hulless oats into the main diet provided an opportunity to recommend its use in the feeding process of age–1+carp in order to increase fish productivity. Originality. The advisability of using hulless oats in the feeding of replacement-brood stock of juvenile carp was studied in Ukraine for the first time. The analysis of productive, physiological and economic indicators has been carried out. Practical value. The results of a comprehensive assessment of piscicultura; and biological parameters provide recommendations for the use of hulless oats in the feeding of replacement-brood stock of juvenile carp. Key words: carp, replacement-brood juvenile stock, feed, feed additives, normalized feeding, physiological needs, fish productivity, feed costs, natural food supply.

Investigation of Cyprinid Herpesvirus 3 (CyHV-3) Disease Periods and Factors Influencing CyHV-3 Transmission in A Low Stocking Density Infection Trial

Cyprinid herpesvirus 3 (CyHV-3) is the etiological agent of koi herpesvirus disease (KHVD) and important pathogen of aquaculture and wild populations of common carp worldwide. Understanding the relative contributions of direct and indirect transmission of CyHV-3 as well as the factors that drive CyHV-3 transmission can clarify the importance of environmental disease vectors and is valuable for informing disease modeling efforts. To study the mechanisms and factors driving CyHV-3 transmission we conducted infection trials that determined the kinetics of KHVD and the contributions of direct and indirect forms of CyHV-3 transmission, as well as the contributions of contact rate, viral load, pathogenicity and contact type. The incubation period of KHVD was 5.88 + 1.75 days and the symptomatic period was 5.31 + 0.87 days. Direct transmission was determined to be the primary mechanism of CyHV-3 transmission (OR = 25.08, 95%CI = 10.73–99.99, p = 4.29 × 10−18) and transmission primarily occurred during the incubation period of KHVD. Direct transmission decreased in the symptomatic period of disease. Transmissibility of CyHV-3 and indirect transmission increased during the symptomatic period of disease, correlating with increased viral loads. Additionally, potential virulence-transmission tradeoffs and disease avoidance behaviors relevant to CyHV-3 transmission were identified.

Dietary Germinated Paddy Rice and Stocking Density Affect Egg Performance, Serum Biochemical Properties, and Proteomic and Transcriptomic Response of Laying Hens Exposed to Chronic Heat Stress

Germinated paddy rice (GPR) could be a good alternative feed source for poultry with stocking density and heat stress problems. A total of 72 Hy-line Brown laying hens raised under low (LSD, 0.12 m2/bird) and high stocking densities (HSD, 0.06 m2/bird) were investigated. Three dietary GPR levels (0, 74 and 148 g/kg) were used. It was found that average daily feed intake, hen-day egg production, and egg mass significantly decreased in the HSD group. The levels of serum glucose (GLU), phosphorous (P), corticosterone (CORT), total Ig, lysozyme (LZY), and superoxide dismutase activities (SOD) in the HSD group were higher than those in the LSD group. Dietary GPR significantly affected GLU, P, alternative complement haemolytic 50 (ACH50), total Ig, and LZY. Moreover, CORT level significantly decreased in 74 and 148 g/kg dietary GPR groups, whereas SOD significantly increased only in the 148 g/kg dietary GPR group. Serum samples were analyzed using liquid chromatography-tandem mass spectrometry, and 8607 proteins were identified. Proteome analysis revealed 19 proteins which were enriched in different stocking densities and dietary GPR levels. Quantitative real-time reverse transcription-PCR technique was successfully used to verify the differentiated abundant protein profile changes. The proteins identified in this study could serve as appropriate biomarkers.