Effects of dietary Benfotiamine on growth and resistance to abrupt shift to higher salinity in the african catfish Clarias gariepinus juvenile

Rey L. Obeda¹, Barry Leonard M. Tumbokon, Augusto E. Serrano, Jr.^1,2*

¹Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

²National Institute of Molecular Biology and Biotechnology, University of the Philippines Visayas, Miagao, Iloilo

*Corresponding author: aeserrano@up.edu.ph

Several studies have identified thiamine deficiency as a factor in the extirpation of some important fish species in the wild. Benfotiamine, a synthetic provitamin B1 and a more bioavailable form, has been demonstrated in fish and shrimps to enhance growth under conditions of high carbohydrate content in the diet. It also enhances immune resistance towards abrupt changes in the environment such as salinity. The present study aimed to determine the effects of elevated dietary carbohydrates and benfotiamine on the fry of the African catfish Clarias gariepinus. Three diets were used, namely, a commercial diet specific for catfish was used as the control diet (Com), a high carbohydrate (HC) diet, and a benfotiamine-supplemented HC diet (HCB). Results show that HCB diet resulted in significantly higher final average body weight (FABW), weight gain (WG), specific growth rate (SGR), and significantly best food conversion ratio (FCR) than the values for both Com and HC groups. In a separate test for attractability, it was demonstrated that HCB was more attractive to the catfish juvenile than did the HC or Con diets. Before subjecting the catfish juveniles to abrupt shift in salinity, an experiment was performed to determine LC50 and was found to be at 11.0 ppt salinity after 42 h. This salinity level was used for the resistance test to abrupt change. The results show that catfish juveniles fed HCB and subjected to salinity change from 0 to 11 ppt exhibited the lowest cumulative mortality while those fed the Con and HC showed higher cumulative mortality. In conclusion, elevating dietary carbohydrates in the diet (i.e., Com to HC diet) did not negatively affect the growth and reproductive performance of the Asian catfish. Further supplementation of benfotiamine at 0.02% to the HC diet enhanced significantly both the growth and resistance to sudden shift to salinity from 0 to 11 ppt.

Keywords: benfotiamine, African catfish, carbohydrates, diet, growth, immune enhancement

EVALUATION OF DIETARY PROBIOTIC Aeromonas sp. A8-29 ON GROWTH PERFORMANCES, FATTY ACIDS COMPOSITION, GUT AND MUSCLE HISTOLOGY OF Tor Tambroides and AND SURVIVAL AGAINST PATHOGENIC INFECTION

Mohammod Kamruzzaman Hossain¹*, Sairatul Dahlianis Ishak¹, Shumpei Iehata²,

NoorDiyana Mat Noordin², Md. Abdul Kader³, Mohammad Asmat Ullah1, Sharifah Noor Emilia2, Yeong Yik Sung⁴, Ambok Bolong Abol-Munafi¹

¹Higher Institution Center of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; ²Faculty of Food and Fisheries Sciences, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia;

 ³Alternative Aquaculture, Melbourne, Australia,

 ⁴Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

*Corresponding author: kjeweldof@gmail.com

Aeromonas sp. considered as pathogenic bacteria, and little information is reported on the use of this bacterial strain as probiotic for fish. Therefore, the aim of the present study was to isolate the autochthonous Aeromonas sp. from the GI tract of the Malaysian Mahseer, Tor tambroides. To reveal the effect of this strain on growth performance, chemical composition, gut histomorphology, and disease resistance of fish were examined after 70 days of feeding trial. Also, the survival of fish were tested through challenge study against two pathogenic bacteria, Aeromonas hydrophila and Vibrio parahaemolyticus. Autochthonous Aeromonas sp. was screened through nutritional enzyme and antimicrobial activity analysis from the GI tract of Tor tambroides and isolates with positive antimicrobial activity were molecularly identified by 16S rDNA sequences. The early juveniles of Malaysian Mahseer were fed with two different diets: one control (Con) with no probiotic, and Aeromonas sp. (TA) enriched with 1X10⁸ CFU g^-1 Aeromonas sp. with three replicates of each treatment. At the end of feeding trial, fish from each tank were challenged against pathogens by intraperitoneal injection with 1X10⁸ CFU ml^-1 pathogen (LD50). Result from the study confirmed that the growth of fish, gut morphology (villus length, height, and width) and survival rate after challenge study in group TA was significantly increased (p>0.05). Fatty acid composition did not differ significantly (p>0.05). The study indicated that dietary supplementation with intestinal autochthonous Aeromonas sp. could positively influence growth performances, gut morphology, and enhance disease resistance of Mahseer against A. hydrophila and V. Parahaemolyticus infection.

Keywords: Aeromonas sp.; antimicrobial; autochthonous probiotic; growth; disease resistance; Tor tambroides

EVALUATION OF DIFFERENT DIETARY STARCH AS CARBOHYDRATE SOURCE ON THE GROWTH PERFORMANCE OF NILE TILAPIA (Oreochromis niloticus) FRY

Quenstein Dizon Lauzon¹, Mary Ann B. Madeja^1*

¹College of Fisheries and Aquatic Sciences, Visayas State University Tolosa, Maharlika Highway, Tanghas, Tolosa, Leyte Phillipines

^*Corresponding author: maryann.madeja@vsu.edu.ph

Aquaculture is considered as the fastest growing industry, however, with the increase in seafood demand, the price of feed increased simultaneously. This has prompted the aquafeed sector to explore alternative ingredients such as plant-based and has contributed to decreased dependence on fish meal. Inclusion of carbohydrates in fish diet promotes growth performance, provide metabolic intermediates for the synthesis of various biological importance and spare dietary protein as a source of energy subsequently channelled to growth. This study aimed to evaluate the effects of carbohydrates on the growth performance and feed efficiency of Nile tilapia fry, O. niloticus. A total of 360 tilapia fry (ABW = 0.10g) were randomly distributed to 9 forty-liter tanks. Tilapia fry were fed with four different diets namely the Control (commercial feed), sweet potato (SP) diet (15% sweet potato starch incorporation), cassava (CS) diet (15% cassava starch incorporation), and corn (15% corn starch incorporation) for 8 weeks. Nile tilapia fed the SP diet exhibited significantly the highest weight gain, final average body weight, and specific growth among other treatments. The lowest FCR was also observed in the SP group. The findings indicated that Nile tilapia fry efficiently utilized the SP diet, enhancing further growth performance and feed efficiency.

Keywords: Sweet potato starch, Oreochromis niloticus, growth performance, carbohydrate diet

Dietary DL-a-tocopheryl acetate enhances growth and resistance against abrupt shift to higher salinity in the Asian catfish (Clarias macrocephalus) juveniles

Barry Leonard M. Tumbokon^1,3, Lemark M. Bautista², Augusto E. Serrano, Jr.^1,3*

^1,3Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

²Pangasinan State University–Binmaley Campus, San Isidro Norte, Binmaley, Pangasinan, Philippines

³National Institute of Molecular Biology and Biotechnology, University of the Philippines Visayas, Miagao, Iloilo

*Corresponding author: aeserrano@up.edu.ph

The effect of dietary supplementation of DL-a-tocopheryl acetate (a-TA) on growth performance, feed efficiency, survival, and salinity resistance of Asian catfish (Clarias macrocephalus) juveniles was evaluated. A total of 750 catfish fry were divided into five treatments with three replicates and fed experimental diets containing varying levels of a-TA: 0, 100, 200, 300, and 400 mg·kg^-1 diet for 45 days. Results show that catfish fry-fed diets supplemented with a-TA exhibited significantly higher weight gain (WG) and final average body weight (FABW), better specific growth rates (SGR) and feed conversion ratio (FCR), and significantly higher survival rates compared to those of the control group fed the basal diet (P < 0.05). Better salinity resistance was observed in the Asian catfish fed the a-TA-supplemented diets when abruptly exposed to higher salinity (10 ppt) for up to 48 h. In addition, the diet attractability test revealed that a-TA-supplemented diets attracted significantly more catfish fry than the basal diet lacking vitamin E (P < 0.05). In conclusion, the results demonstrated that dietary supplementation of a-TA (i.e., vitamin E) improved growth, feed efficiency, feed attractability, survival, and resistance to abrupt higher salinity exposure of Clarias macrocephalus juveniles.

Keywords: bighead catfish, juveniles, salinity challenge, survival, vitamin E

MICROANATOMY OF THE DIGESTIVE SYSTEM INTHE STRIPED ACORN BARNACLE AMPHIBALANUS AMPHITRITE FROM LIBONG ISLAND, THAILAND

Romfa Kaewnuan¹*, Chanyut Sudtongkong¹, Pornthep Wirachwong1, Supparat Kong-Oh¹ , Nattawut Charoenphon², Gen Kaneko³, Piyamat Kongtueng⁴, Kitiya Kongthong⁵, Sinlapachai Senarat¹

¹Department of Marine Science and Environment, Faculty of Science and Fisheries Technology, Rajamangala University of Technology Srivijaya, Trang, Thailand Agriculture

²Department of Anatomy, Faculty of Medical Science, Naresuan University, 65000 Thailand

³College of Natural and Applied Science, University of Houston-Victoria, Victoria, Texas, USA

⁴Central Laboratory, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand

⁵Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand

*Corresponding author: romfakaewnuan@gmail.com

The striped acorn barnacle Amphibalanus amphitrite is commonly found in Thailand; however, its digestive biology has never been explored. The objective of this study was to describe the microanatomy, classifying digestive cells in A. amphitrite using histological methods. All samples (n = 30) were obtained from the seagrass beds, Libong Island, Thailand, which is an important seagrass site to support dugong populations, during January to March 2021. Histological observation of longitudinal sections showed that the digestive system of A. amphitrite consisted of a digestive tract and accessary organs. The digestive tract was mainly divided into four sub-regions including the cuticle-lined mount, esophagus lining with a high columnar epithelium, stomach and intestine. The arrangement of stomach and intestine was U-shape, and their sizes were prominent. Both were lined with a simple columnar epithelium, but the longitudinal fold was prominent in the intestine than stomach. The accessary organs, including the digestive gland, showed a pair of lobulated structure and were widely located between the esophagus and stomach. In cross sections, each gland was covered with low columnar epithelial cells on the thin layer of smooth muscle.

Keywords: Acorn barnacle, Histology, Libong Island, Stomach structure, Thailand

BENFOTIAMINE IN HIGH CARBOHYDRATE DIET ENHANCES GROWTH AND REPRODUCTIVE PERFORMANCE OF THE ASIAN NATIVE CATFISH (Clarias macrocephalus)

Lemark M. Bautista^1,2*, Barry Leonard M. Tumbokon⁴, Mojena M.G.

Plasus³, Augusto E. Serrano, Jr.^1,4

¹Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, Philippines

²Pangasinan State University - Binmaley Campus, San Isidro Norte, Binmaley, Pangasinan, Philippines

³Western Philippines University, Puerto Princesa City, Palawan

⁴National Institute of Molecular Biology and Biotechnology, University of the Philippines Visayas, Miagao, Iloilo

*Corresponding author: lmbautista2@up.edu.ph

Clarias macrocephalus has been extirpated in most regions in the Philippines and as a preliminary study towards its reintroduction, we aimed at enhancing the growth and reproductive performance of the broodstock. Several studies have identified thiamine deficiency as a factor in the extirpation of some important fish species in the wild. The present study aimed to determine the effects of elevated dietary carbohydrates and benfotiamine, a more bioavailable analog of thiamine (vitamin B1). Three diets were used, namely, a commercial diet for catfish was used as the control diet (Com), a high carbohydrate (HC) diet, and a benfotiamine-supplemented HC diet (HCB). Results show that survival of catfish in captivity for 10 weeks was remarkably high, exhibiting an average of 99% for all three treatments (P>0.05). HCB diet resulted in significantly higher final average body weight (FABW), weight gain (WG), specific growth rate (SGR), and significantly best food conversion ratio (FCR) than the values for both Com and HC groups (P>0.05). For the reproductive performance, female Asian catfish fed the HCB diet exhibited significantly heavier ovary and liver, higher GSI and fecundity than those female catfish fed either the Com or HC diet (P>0.05). In the male catfish, testes were significantly heavier in the HCB group. HSI, male LW, LL, and GSI were significantly higher in the HC and HCB groups than in the Com group (P<0.05). The larval survival rate was significantly higher in the Asian catfish fed the HCB diet than in those fed the Com or HC diet (P>0.05). In conclusion, elevating dietary carbohydrates in the diet did not negatively affect the growth and reproductive performance of the Asian catfish. Further supplementation of benfotiamine to the HC diet enhanced significantly both the growth and reproductive performance of the Asian catfish.

Keywords: Benfotiamine, Asian catfish, Carbohydrates, Diet, Growth, Reproduction