A review of betanodavirus vaccination as preventive strategy to viral nervous necrosis (VNN) disease in grouper

Viral disease outbreak is the most serious issue as it may cause severe losses to farmers as well as to economy in the marine industry worldwide. Among fish viral diseases, betanodavirus is a significant pathogen that causes viral nervous necrosis (VNN) and can result in mass mortalities to fish culture especially at larval stages. In Malaysia, betanodavirus had been isolated from groupers, seabass, red snappers, and golden pomfret. Recently, inconsistent seed supply is observed due to viral infection at larval stages which limits the growth of fish culture. Therefore, seeds of grouper are often imported from neighboring countries such as Indonesia by farmers. Strict importation regulations should be practiced as the importation of fish seeds may become a possible source of the virus entering the country. It is a challenge to track farmers who are affected by the disease in order to segregate or eliminate the VNN carrier spawners. This scenario had resulted in incomplete destruction of diseased fish population and leads to re-occurrence of the disease at the early stage of grouper. This situation warrants immediate attention to develop promising prevention strategies such as a new vaccine which is very important and could work effectively with better farm management approaches. This article discusses the occurrence of viral nervous necrosis (VNN) disease in Malaysia and reviews possible preventive measures via vaccination to combat the disease

Palm date meal as a non-traditional ingredient for feeding aquatic animals: A review

Protein ingredients in aquafeed are one of the most important factors responsible for the development and sustainability of aquaculture. Currently, because of high costs and fluctuating production, some animal and plant protein sources are unable to satiate the increasing demand from the fish feed manufacturers. Aquatic animals’ nutritional requirements have been accorded particular focus with less costly feedstuff in aqua feed given extra weightage. There has been increasing attention in recent years on finding methods to recycle the animal and plant by-products for feed preparation. Due to its vital amino acid content as well as high protein composition, palm date meal (PDM) which is a renewable and sustainable resource is expected to be a viable raw material option for replacing protein ingredients (e.g., fish meal and soybean meal) or as a supplement in fish feed. PDM is an agro-industry by-product which left from dates as waste in several countries. This article reviewed the current research including the source, derivatives, and the potential of PDM as a possible alternative to the conventional plant and animal protein sources. Also, the added value of using PDM waste in aquafeed to reduce the feed cost, enhance this e growth rate of fish, improve the health and well-being of fish, and subsequently sustain the aquaculture industry. Therefore, this review paper will illuminate the possibility of PDM as a promising feed source and also the present knowledge and future perspectives about the application of PDM in aquaculture

Pengekstrakan keseluruhan daripada sampel ikan menggunakan kaedah asal dan modifikasi shirzadegan et al.(1991)

Kajian ini dilakukan bagi mengenalpasti kaedah pengekstrakan yang sesuai digunakan untuk mengekstrak RNA dari sampel tisu ikan. Terdapat tiga kaedah yang telah diujikaji iaitu kaedah reagen TRIZOL, kaedah asal Shirzadegan et al. (1991) dan kaedah modifikasi Shirzadegan et al. (1991). Dalam kajian ini, ketiga- tiga kaedah tersebut digunakan untuk menguji ketahanan sampel ikan bagi menentukan tempoh masa yang sesuai untuk mengekstrak RNA bagi sampel yang disejukbekukan. Walaupun kaedah reagen TRIZOL merupakan kaedah yang efektif dalam mengekstrak RNA dari sampel manusia, tumbuhan dan haiwan, namun setelah digunakan untuk mengekstrak RNA dari sampel tisu ikan, kualiti RNA yang didapati adalah rendah berbanding dengan kaedah Shirzadegan et al. (1991). Dalam kajian ini juga, kaedah pengekstrakan RNA yang telah dioptimumkan daripada kaedah asal Shirzadegan et al. (1991) telah diperkenalkan. Antara pengoptimuman yang dilakukan pada kaedah modifikasi Shirzadegan et al.(1991) ialah (1) pengurangan masa pengemparan, (2) pengurangan masa pemendakkan RNA, dan (3) penambahan langkah pencucian pelet RNA. Kaedah modifikasi Shirzadegan et al. (1991) dapat menghasilkan jumlah RNA sebanYak 75 - 791 µg I g tisu ikan, bergantung kepada tisu ikan yang digunakan. Selain itu, ketahanan penimbal lisis juga diuji dengan mengekstrak sampel ikan berdasarkan tempoh masa penyimpanan penimbal lisis pada suhu 4°C. Penimballisis ini mengandungi 0.1 M LiCl, 1 % SDS, 0.1 M Tris-HC1, 0.01 M EDT A dan fenol. Ia boleh digunakan sebagai kaedah pengekstrakan RNA altematif yang murah dan mudah dikendalikan. Penimballisis dapat disimpan selama lebih dari 2 bulan pada suhu 4°C. Kesimpulannya, kaedah modifikasi Shirzadegan et al. (1991) boleh digunakan sebagai kaedah altematif untuk mengekstrak RNA dari sampel ikan tanpa melibatkan penggunaan kit pengekstrakan RNA yang komersial

Screening of Infectious Hypodermal and Haematopoietic Necrosis Virus (IHHNV) infections in wild freshwater prawn, Macrobrachium Rosenbergii, in Malaysia / Hazreen Nita binti Mohd Khalid

Infectious hypodermal and haematopoietic necrosis virus (IHHNV), so called Penaeus stylirostris densovirus (PstDNV) has been detected widely in penaeid culture facilities in Asia and the Americas. A study by Hsieh et al. (2006) reported that infection of IHHNV on sub-adult and postlarvae of the giant freshwater prawn, Macrobrachium rosenbergii in Southeast Taiwan caused high mortalities of up to 80 %. Eosinophilic intranuclear inclusion bodies were also found on the connective tissues between epithelial cells of the infected samples. In Malaysia, although there is no report of IHHNV infection in M. rosenbergii, preliminary works warrant urgent need to setup a screening protocol for IHHNV for both wild and cultured populations of the species. Studies on screening of IHHNV in giant freshwater prawn were conducted in selected hatchery and wild environment throughout 2009/2010. The purpose of this study was to determine the prevalence of IHHNV in giant freshwater prawn broodstocks in Malaysia by standard polymerase chain reaction (PCR), nested PCR, histopathology and in situ hybridization. PCR screening using standard protocol from OIE was carried out in a prawn hatchery in Perak. Six out of thirty samples (20 %) of random sampling wild berried M. rosenbergii taken directly from Sungai Perak which used as broodstocks in the hatchery were identified as positive with IHHNV infection. Sequence alignment of these positive isolates (389-bp) (GenBank Acc. No. HM536212) in GenBank revealed close identities (98%) to Taiwanese IHHNV strains isolated from M. rosenbergii in Taiwan (GenBank Acc. No. DQ057983). Screening of IHHNV in wild environment were also been conducted where fifty wild-caught giant freshwater prawns were collected monthly (2009/2010) from two selective locations; Sungai Rubana (Perak), and Sungai Timun (Negeri Sembilan). The detection was conducted by nested PCR which based on the iii standard PCR suggested by OIE (OIE, 2003) while for the nested step, newly designed primers were used. Through the year 2009/2010, the prawns captured from Sungai Timun and Sungai Rubana showed positive by nested PCR with prevalence of 64.4 % and 48.7 % respectively. Sequence of positive samples were aligned together with available IHHNV sequences obtained from GenBank and phylogenetic tree was generated which revealed that Malaysia isolates of M. rosenbergii is clustered together with Taiwanese strain (DQ057983). Histopathology examination revealed low intensity of eosinophilic intranuclear inclusion bodies in connective tissues of epithelial cells in hepatopancreas and muscle tissue in some of the samples. An additional method, in situ hybridization (ISH) was also included in the study in order to confirm the findings of histopathology. However, due to lack of positive control of other prawn viruses, this method is unsuccessful to be optimized and further validation cannot be performed. Further investigation in improving this method is necessary as ISH could provide greater diagnosis sensitivity than other conventional histology methods. Results obtained in this study revealed that IHHNV infection were common in adult prawn in both Sungai Rubana and Sungai Timun. The economic impact caused by IHHNV in wild-caught M. rosenbergii was unknown as all the infected samples did not show any mortality. However, the gross sign such as deformity of rostrum and pleopods were seen in the infected prawn. The present study has successfully identified the partial sequence of ORF1 IHHNV genome which leads to the early documentation on the occurrence of IHHNV infection in giant freshwater prawn in Malaysia. To date, there is no definite treatment for this disease, thus frequent screening program of viral disease in prawn should be conducted in order to control the spread of the disease

Epidemiology of emerging diseases and disorders in cage cultured Pangasius spp. in Pahang, Malaysia

Pangasius hypophthalmus or famously known by local Malaysians as Patin Hitam is one of the most important sources of food in Malaysia. It is widely cultured in the Peninsular Malaysia especially in Pahang as Patin is a popularly consumed freshwater fish. Global economic interest in the fish has increased its demand in the USA and Europe. However, high mortality due to bacterial and viral infections is the main problem that needs to be solved. Therefore, bacteria in P. hypophthalmus in Pahang is being focused with the factors connected to the prevalence of bacteria and virus in P. hypophthalmus. This research was conducted for two cycles (February–September 2016 and January–August 2017) in different farms in Temerloh and Pekan, Pahang. Bacteria and virus samples were taken from three organs of Patin Hitam which are kidney, liver and spleen. Physical parameters for water quality was measured using a multi-parameter probe sensor (YSI, USA) and chemical parameters were analyzed with DR900 colorimeter (Hach, USA). Bacteria samples were identified using biochemical test kits, API 20NE and 20E, followed by confirmation of the bacteria using Polymerase Chain Reaction (PCR). Virus samples were identified using conventional PCR. There were several bacteria isolated throughout the culture period. The highest prevalence of bacteria found was Aeromonas hydrophila (63%0 followed by Photobacterium damselae (23%), Plesiomonas shigelloids (7%), Pseudomonas luteola (4%) and Pseudomonas fluorescens (3%). There was no virus isolated from these two sites in Pahang River. The susceptible size of Pangasius spp. that was infested by A. hydrophila was 300-400g. Furthermore, risk factors affected the presence of bacteria were different at all sites. However, only ammonia was presence throughout the sampling period at all sites. Sulfide, nitrite, iron and ammonia were were the most significant parameters that have strong associations with the presence of A. hydrophila. Significantly, these results could contribute to better treatment of fish disease and development of standard operating procedure of future fish culture for early disease prevention

Coconut Palm: Food, Feed, and Nutraceutical Properties

The price of traditional sources of nutrients used in animal feed rations is increasing steeply in developed countries due to their scarcity, high demand from humans for the same food items, and expensive costs of raw materials. Thus, one of the alternative sources is coconut parts or coconut as a whole fruit. Coconut is known as the ‘tree of abundance’, ‘tree of heaven’, and ‘tree of life’ owing to its numerous uses, becoming a very important tree in tropical areas for its provision of food, employment, and business opportunities to millions of people. Coconut contains a rich profile of macro and micronutrients that vary depending on the parts and how they are used. It is frequently chosen as an alternative source of protein and fiber. Its uses as an antibacterial agent, immunomodulant, and antioxidant further increase its importance. Using coconut oil in ruminant feed helps to minimize methane gas emissions by 18–30%, and to reduce dry matter intake up to 4.2 kg/d. The aquaculture sectors also use coconut palm as an alternative source because it significantly improves the digestion, growth, lipid metabolism, health, and antioxidative responses. However, coconut is not widely used in poultry diets although it has adequate amount of protein and carbohydrate due to anti-nutritional factors such cellulose (13%), galactomannan (61%), and mannan (26%). This review considered the importance and potential of coconut usage as an alternative ingredient in feed and supplements in various livestock sectors as it has plentiful nutrients and functional qualities, simultaneously leading to reduced feed cost and enhanced production

Olive oil by-products in aquafeeds: opportunities and challenges

The increment in world population has led to the increasing demands for fish supply as principal source of animal protein that represents about 17% of animal protein consumption globally. The world aquaculture industry has expanding remarkably but limited source of fishmeal and fish oil which known as important ingredients in fish feed has led to seeking of alternative sources for their replacement in aquafeed formulation. Many potential and cheaper ingredients derived from vegetable oils or agricultural by-products have been investigated to replace fish meal and fish oil which shown promising results in fish productivity and fish health status including olive oil by- products. Varies depending on its type, olive oil composes of antioxidants, healthy type of fats such as MUFA and PUFA, and high in vitamins that provide human health benefits for heart and liver, help in many diseases and reducing the risk of cancer. In agriculture industry, olive and olive oil production processes have resulted to by- products such as olive mill wastewater (OMW), olive leaf and olive pomace. The inclusion of these by-products in animal feeds is the solution for agricultural waste management. The first report of utilization of olive oil by- products in fish feed was documented in 2004 and since then, many researches has been conducted to investigate fish health benefits that showed improvement in fish carcass composition and fish immunity depending on type of by-products used and fish species. Additionally, antioxidant contents in olive oil extract were reported could provide antimicrobial, antifungal and antioxygenic characteristics which potentially improve the fish health. This review discussed the opportunities and challenges in application of olive oil by-products in aquafeed which provides significant prospects in fish growth performance that could boost aquaculture industry development