The maturation of male fish is a problematic aspect of Clarias macrocephalus and probably one of the causes of the population’s disappearance in the usual places where they once abound. The present study aimed to explore feed additives to enhance its maturation from puberty. Vitamin E (VE) is essential in the reproduction of animals, including fish. A growth trial was conducted in which groups of C. macrocephalus were fed experimental diets containing graded levels of VE in the form of α-tocopheryl acetate (α-TA), namely, 0, 100, 200, 300 and 400 mg VE·kg-1 diet. After 90 days, growth and maturation were assessed, and reproductive performance was tested by conducting induced spawning and artificial fertilization. Results showed growth and nutrient utilization indices were better in groups fed diets containing VE than in the control group. Maturation indices such as GSI, gonad weight, lengths, egg diameter, and fecundity were enhanced in the VE-treated groups. Reproductive performance, such as fertilization, hatching, and larval survival rate, was enhanced in C. macrocephalus broodstock in VE-treated groups. Quantitative estimates for optimal VE dose that elicited maximal response values ranged from 202.1 to 230.0 mg VE·kg-1 diet.

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 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 survival of the subadult 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) (P<0.05) 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 (P<0.05) than those female catfish fed either the Com or HC diet (P>0.05). GSI of the female catfish and fecundity were significantly higher in the HCB group (P<0.05) than in the Com or HC group (P>0.05). In the male catfish, testes were significantly heavier in the HCB group (P<0.05) than in the Com or HC diet (P>0.05). HSI, male LW, and LL were significantly higher in the HC and HCB groups (P>0.05) than in the Com group (P<0.05). GSI values of the male catfish were significantly highest in the HCB (P<0.05), followed by the HC group, and significantly lowest in the Com group (P<0.05). The larval survival rate for one week was significantly higher (P<0.05) 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 from 7.70% to 22.73% (i.e., Com to HC diet, respectively) 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 reproductive performance of the Asian catfish.

The effect of dietary supplementation of DL-alpha-tocopheryl acetate (a-TA) on growth performance, feed efficiency, survival, and salinity resistance of Asian catfish (Clarias macrocephalus) fry was evaluated. A total of 750 catfish fry were divided into five treatments with three replicates and fed experimental diets containing varying levels of alpha-TA: 0, 100, 200, 300, and 400 mg·kg-1 diet for 45 days. Results show that catfish fry-fed diets supplemented with alpha-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 alpha-TA-supplemented diets when abruptly exposed to higher salinity (10 ppt) for up to 48 h. In addition, the diet attractability test revealed that alpha-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 alpha-TA (vitamin E) improved growth, feed efficiency, feed attractability, survival, and resistance to abrupt higher salinity exposure of Clarias macrocephalus fry.

The study aimed to determine the effect of feeding dietary ulvan on some genes and pathways of Penaeus vannamei juveniles. Feeding a diet containing ulvan at 1.0 g·kg-1 resulted in differentially expressed genes (DEGs) between the treatments and the control group. Ulvan resulted in 53 DEGs with 26 up and 27-down-regulated DEGs. The DEGs were immune-related, while several affected the energy and substrate metabolic pathways. Specific genes upregulated were Glycerol-3-phosphate acyltransferase (GPAT) of the glycerolipid synthesis, centrosomal protein 120 involved in cell cycling and other activities, RNA helicase, an enzyme involved in opening up DNA molecules, ATP-binding cassette, TATA-binding protein, taurine transporter, transcriptional enhancer factor (TEF), C-type lectin among others. Down-regulated genes included gamma-crystallin, which acts as molecular chaperones; catenin alpha, which is involved in adhesion complex; dystrophin, which is involved in scaffolding for several signaling molecules; and maintenance muscle integrity, among others. Top DEGs that affected significantly important pathways include TEAD (transcriptional enhancer factor domain), GSK3B (glycogen synthase Kinase 3 beta), SLC6A1 (i.e., solute carrier Family 6 Member 1), and ADCY2, which affected signal transduction, environmental adaptation as well as the endocrine, immune, nervous, and digestive systems. In conclusion, dietary ulvan resulted in the up-regulation of immune-related DEGs, which could probably be used to adapt to unfavorable conditions and also affected some energy and substrate metabolic pathways that could potentially be used to direct the overall metabolism.

This study aimed to assess the effects of 17α-methyltestosterone (MT) on the growth and reproductive performance of male Asian catfish (Clarias macrocephalus). A total of 36 immature male Asian catfish (ABW = 125.97 g) were randomly distributed into 12 circular tanks, and fed with either the control diet (with no MT) or diets containing MT at 60 mg·kg-1, 90 mg·kg-1, or 120 mg·kg-1 for 45 days. Results showed that weight gain (WG), specific growth rate (SGR) and feed intake (FI) were significantly higher in the male catfish fed with diets containing 60 and 90 mg·kg-1 MT than in those fed with the control diet. Also, the diet attractability test revealed that the 60 and 90 mg·kg-1 MT groups significantly attracted more catfish than did the control diet; however, increasing MT to 120 mg·kg-1 reduced its attractability to the immature male catfish. MT-treated male catfish exhibited significantly heavier and significantly longer testes than male catfish fed the control diet at the termination of the feeding trial. These male catfish also exhibited significantly higher gonadosomatic indices (GSI) than catfish in the control group. Following induced spawning of nontreated female catfish and artificial fertilization of its eggs using testis preparation from the experimental male catfish at the termination of the feeding trial, results showed that testis preparations from all MT-treated males resulted in significantly higher fertilization (FR) and hatching rates (HR) of the eggs. In conclusion, incorporating MT to the diet improved both the growth and reproductive performance of the male Clarias macrocephalus. Precisely, dosages of optimal dietary MT using a quadratic model for maximal SGR, GSI, FR, and HR values were estimated to be 58.3, 75.0, 90.6, and 78.2 mg·kg-1, respectively.

We studied the mechanism of the effects of 17α-methyltestosterone (MT) on previously reported enhanced growth and maturation of the Asian catfish Clarias macrocephalus. A total of 18 pubertal male (3 fish·tank-1) catfish (ABW=125.97 g) were stocked into six experimental circular tanks and fed with a basal diet (control) or a basal diet containing 60 mg MT kg-1 diet for 90 days. At the termination of the experiment, livers were excised, and total RNA was extracted, evaluated, and reverse transcribed to cDNA. Six libraries of cDNA (3 for the control and 3 for the MT-treated group) were subjected to bioinformatics. Differentially expressed genes (DEGs) were identified using similarity scores of the de novo assembled transcript with those in the seven public databases. There were 141 up- and 72 down-regulated DEGs, mostly belonging to uncharacterized/not yet identified proteins. Thus, DEGs in the top enriched KEGG pathways were used to characterize the effects of MT. Upregulated DEGs included tyrosine hydroxylase (TH), Cytoplasmic Polyadenylation Element Binding (CPEB), Fas-associated death domain (FADD), Major Histocompatibility Complex class 1 (MHC-1), other immune-related genes, among others. Down-regulated DEGs included Cytochrome P450 family one subfamily A member 1 (CYP1A1), Alternative oxidase (AOX), UDP-glycosyltransferase (UGT), Acyl-CoA Synthase Bubblegum Family Member 1 (ACSBG), Stearoyl-CoA Desaturase (SCD), among others. In conclusion, MT-treated male Clarias macrocephalus exhibited up-regulation of some pathways protecting cellular conditions like cell proliferation, survival, development and homeostasis processes, for development and homeostasis processes. MT also affected changes in bile acid production and the inhibition of the production/conversion of testosterone. MT resulted in the down-regulation of a serotonergic system that possibly affected gonadal development, inhibition of the retinoid enzyme that would otherwise diminish the full effects of MT or its metabolite, and inhibition of the formation of estrogen, leading to down-regulation of several estrogen-related KEGG pathways.

The present study aimed to elucidate the mechanism of protection provided by dietary ulvan as observed in previous studies. Thirty shrimps (3.35 ± 0.08 g average body weight) were stocked in six polyethylene tanks (5 shrimps tank-1, treatments were in three replicate/tank) and were fed either a diet containing no ulvan (control) or containing ulvan at 1 g kg diet-1 for 35 days at 10% body weight twice daily. At the termination of the feeding, the shrimps were subjected to a white spot syndrome virus (WSSV) challenge test via intramuscular injection of the viral inoculum. Shrimps were sacrificed after 24 h of exposure, and the hepatopancreas was excised for total RNA extraction for transcriptome profiling. Biological validation of the RNA-seq results was also performed for 10 immune-related genes (6 up- and 4 down-regulated genes). A comparison of the ulvan group with the control group revealed that 69 differentially expressed genes (DEGs) were significantly up-regulated, whereas 640 were significantly down-regulated. 184 DEGs between the control and ulvan-treated groups were classified into six KEGG categories of Metabolism (145 DEGs), Organismal systems (16), Human disease (4), Genetic Information Processing (10), Cellular Processes (2), and Environmental Information Processing (7). The 145 DEGs under Metabolism were distributed to Level 2 subcategories as carbohydrate metabolism (59 DEGs), global and overview maps (44), energy metabolism (27), and amino acid metabolism (15). All candidate immune-related genes (67) were down-regulated except for 5 genes. The validation experiment showed proportionality of gene expressions of the qPCR and of those in the assembled transcriptome, justifying the acceptability of the RNA-seq results. In conclusion, data from the present study provided mechanisms for protecting the white shrimp by dietary ulvan against WSSV infection.

The study aimed to determine the optimum dietary lysine level of the orange-spotted rabbitfish Siganus guttatus Bloch, 1787 (average body weight range of 5.2 to 7.6 gxfish-1). The feeding trial was conducted for 8 weeks employing six experimental diets which were isonitrogenous, isocaloric, and isolipidic (35% crude protein (CP), 18.3 MJxkg-1 of gross energy, and 5% lipid). The lysine content ranged from 1.22 g to 2.12 g lysine xkg-1 dry diet (35 to 70 gxkg-1 CP). Results showed that percent weight gain (PWG), and specific growth rate (SGR) peaked at a lysine level of about 55 gxkg-1 CP equivalent to 1.93 gxkg dry diet-1). Feed efficiencies i.e., protein efficiency ratio and food conversion ratio values as well as survival were not affected by the dietary treatments. Lysine requirement level for juvenile rabbitfish was estimated using both broken-line and quadratic regression analyses of PWG and SGR against dietary lysine levels to be between 15.9 and 18.3 gxkg-1 diet (=45.3 and 52.3 gxkg-1 CP).

One of the most significant inputs in an aquaponic system is fish feed. Here, two satiation feeding (SF) levels (60% & 50%) have been tested. It aims to determine its effect on the water quality and the growth, hematological indices, and blood chemistry of Nile tilapia Oreochromis niloticus reared in nutrient film technique aquaponic system (NFTAS) containing upland kangkong Ipomea reptans within 1 month period and compared it in the recirculating system (RS). Results showed that the SF levels have an insignificant effect on the water quality between the systems mainly due to the nonoptimal pH level that influenced the nitrification efficiency and the inefficient uptake of nutrients by the plants in NFTAS. Consequently, the growth, hematological parameters, and blood chemistry of the fish reared in NFTAS have not improved compared with those in RS. However, the fish and the plant growth performance were better at 60% SF in both systems. Thus, 60% is suggested SF level when 200 individuals Nile tilapia O. niloticus tilapia fingerling (2.46 g, average initial weight) are reared within 31 days in a healthy and balanced NFTAS with 50 individuals upland kangkong I. reptans.

The hatching of fairy shrimp Branchinella thailandensis from Thailand was studied. The fairy shrimp cysts were subjected to different temperature regimes [ambient (26-29°C), 30°C, 32°C, and 34°C] and examined the experimental condition’s effect on hatching until no hatching occurred. Results indicated that temperature affects the hatching of the Thai fairy shrimp B. thailandensis cysts. The hatching of the fairy shrimp could occur once at 34°C and can be stimulated at 32°C, but fluctuating temperatures (26-29°C) and 30°C may reduce hatching success. However, the incubation period took longer, and hatching success was extremely low, suspected of improper cysts production technique and processing. In conclusion, the hatching of fairy shrimp B. thailandensis can be improved at 34°C but optimal at 32°C.

The study aimed to determine the lysine requirement of young spotted scat Scatophagus argus (Linaeus, 1776) (average body weight = 10.7 g). The feeding trial was conducted for 8 weeks with 5 experimental diets which were isonitrogenous, isocaloric and isolipidic (35% CP, 18.3 MJ.kg-1, containing lysine levels as treatments containing equal dietary protein (35%) and lipid levels (5%) in 3 replicates. The lysine content was from 1.22 g to 1.94 g lysine.kg(-1) dry diet (35 to 55 g-kg(-1) CP) with an average content of 0.18 g lysine.kg(-1) dry diet per treatment. Results showed that the growth rate, feed conversion and protein efficiency ratios were significantly highest at lysine level of 1.58 g.kg dry diet(-1) (45 g.kg(-1) CP). Fish survival was not influenced by dietary lysine. Lysine requirement level for juvenile scat was estimated using quadratic regression of the percent weight gain (PWG) and specific growth rate (SGR) against dietary lysine level to have a mean value of 1.64 g.kg dry diet(-1) (4.75 g.kg(-1) CP).

This study aimed to investigate the effect of acidifying the diet of black tiger shrimp Penaeus monodon on its growth and feed efficiency by supplementing coconut sap vinegar CSV) or sugar cane vinegar (SCV) or their 1:1 combination. Three hundred and sixty post larva shrimps (average initial weight of 0.01g) were randomly distributed into 12 50-L plastic containers. Four experimental diets, namely, control diet, 2% CSV, 2% SCV and 2% CSV+SCV were fed to groups of shrimps. After 90 days, all shrimps fed with diets containing vinegar exhibited significantly higher final average body weight (FABW), weight gain (WG), feed intake, specific growth rate (SGR), and better feed conversion ratio (FCR) than those fed the control diet. Attractability tests showed that the CSV and CSV+SCV diets attracted significantly the highest percentage of shrimps after 10 min of feed placement. Survival rate was not significantly different among the treatments. In conclusion, the results demonstrated that the vinegars tested could be used as growth enhancers in shrimp and that the combination of coconut sap and sugar cane vinegars supplemented to the diet resulted in the best growth and feed efficiency as well as attracted the most percentage of shrimps.

Two onsite tests were carried out to determine the effects of varying dietary protein to energy (P:E) ratio in intensive culture of Nile tilapia in two different places at two stocking densities. In both field trials, three diets were used namely commercial (CM) diet, control (CO) diet containing no Rhizoclonium and a diet containing Rhizoclonium replacing 52% of soybean meal (RLP); the diets contained decreasing P:E ratio of 21, 16 and 12 gMJ-1, respectively. The first trial was conducted in Aklan, Philippines at a stocking density of 17 fishm-2 while the second was in Pangasinan, Philippines at 27 fishm-2. In both trials, the three diets were fed for 2 months to 3 replicate cages of Nile tilapia, all of which were randomly placed in about 1.0 ha fresh water fish pond. In the first trial in Aklan, at 17 fish m-2 stocking density, no significant differences in the parameters were observed except in the absolute growth rate (AGR) in which the RLP dietary treatment exhibited a higher value than did either the CM or the CO diet. In Pangasinan, at 27 fish m-2 stocking density, significant differences in TFI, DFI and SGR were observed, all the other parameters were statistically similar. The RLP group exhibited lower total feed intake (TFI) and daily feed intake (DFI) but higher specific growth rate (SGR) than did either the CM or CO diet. In either stocking densities, feed cost was the main determinant of profitability in which the RLP group resulted in significantly highest profitability i.e., lowest total production cost, highest gross income and highest profit and profit margin. Although profit was significantly higher in the higher stocking density, profit margin was significantly higher in the lower stocking density. There was no statistical interaction between dietary treatment and stocking density as analyzed by two-way analysis of variance.

Acute hyposalinity stress in shrimp ponds is a natural occurrence during the rainy season and the provision of functional ingredients that will elicit resistance to this stress is needed. Quillaja saponin (QS), a triterpenoid saponin derived from the bark of Quillaja saponaria, is reported to trigger innate immunity in vitro and in vivo in shrimps. The present study aims to evaluate its potential as growth-promoter and its immune-enhancement effects against salinity stress. Three separate experiments were done: (a) an attractability test; (b) a 30-day feeding trial to determine optimal inclusion of QS; and (3) an acute hyposalinity stress test following feeding the experimental diets. Attractability tests showed that all the Quillaja saponin inclusions significantly attracted more shrimps than the control diet (p<0.05). In the feeding trial, 5 experimental diets containing 0.0, 0.15, 0.30, 0.45, and 0.60 g kg-1 QS (QS 0, QS 15, QS 30, QS 45 and QS 60, respectively) were fed to groups of shrimps. Results showed that the final average body weight (FABW), feed intake (FI), weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER) values of shrimps in the QS 30 and 45 groups were significantly higher than that of the control group; the values of those in QS 15 and 60 groups were not significantly different from those of the QS 0 group. The optimal inclusion level of dietary QS was estimated to be 0.36 g kg-1. In the acute hyposalinity stress test, shrimps were fed with the experimental diets for 2 weeks and then transferred from 24 PSU salinity media to 2 PSU. All QS groups showed lower cumulative mortality rate than that of the QS 0 group except for the QS 60; QS 30 groups exhibited significantly the lowest. The estimated level of QS that elicited the lowest cumulative mortality rate was 0.33 g kg-1. In conclusion, the diets containing QS enhanced the shrimp’s attractability, promoted both growth and immune response against acute hyposalinity stress at the optimal level of 0.36 g kg-1 QS in the black tiger shrimp P. monodon.

Two feeding trials were conducted to investigate the effects of dietary pH (pH 2.5, 3.7, 4.6, 5.7-control, pH 7.0, and pH 8.0) and dietary acid source (acetic acid, citric acid, hydrochloric acid and control-no acid) on growth rate and feed utilization efficiency of the Nile tilapia fry. In addition, attractability of the diets at different pH and dietary acid sources were determined. Results of the first feeding trial showed that the feed with pH adjusted to 4.6 resulted in significantly highest final average body weight (FABW), weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and most efficient food conversion ratio (FCR) in the Nile tilapia fry. Survival was 100% in diets with pH 3.7 up to 7.0; the diet with pH 2.5 exhibited significantly lowest survival followed by the pH 8.0 diet. In the second feeding trial, diets that contained hydrochloric, citric or acetic acids that were used to adjust the pH to the optimal 4.6 resulted in higher FABW, WG, SGR, and PER values but lower FCR values than did the control diet; these parameters were not significantly different among the dietary groups. This study demonstrated that the dietary pH promoted growth and efficiency in the Nile tilapia fry and that the three acids that were used were similar in their effects on growth and efficiency. Furthermore, it was demonstrated that either acidifying the diet to pH 4.6 by an inorganic acid such as HCl or the provision of a dietary acidifier such as citric acid or acetic acid could enhance growth, feed efficiency and survival of the Nile tilapia.

The present study aimed to evaluate the effects of high carbohydrate diet in the absence of presence of dietary benfotiamine on growth and immune response against ammonia toxicity (50 mg NH4Cl L-1, average ambient temperature=27oC, pH 8.3) of post larval Penaeus monodon. A feeding trial involving three dietary treatments followed by an ammonia toxicity tests and a feed attractability test were conducted separately. During the feeding trial, shrimps were fed three experimental diets, namely, (1) a diet containing 15% starch (C), (2) a diet with 25% corn starch (high carbohydrate diet, HC) and (3) a diet containing both 25% starch supplemented with 0.2 g kg-1 benfotiamine (HCB). At the termination of the feeding trial, the shrimps were subjected to ammonia toxicity test to determine the effects of the diets on the immune response of the post larval shrimps. Attractability tests using customized aquaria showed that the HCB diet elicited significantly the highest attractability even after 10 min of feed placement in the feeding chamber. In the feeding trial that lasted for 60 days, results showed that shrimps fed with diet containing HCB exhibited significantly the highest growth rate (p<0.05) among all groups of shrimps in terms of final average body weight (FABW), weight gain (WG), and specific growth rate (SGR); they also exhibited significantly the highest feed intake (p<0.05). Upon challenge of the shrimps with 50 mg L-1 ammonia, shrimps fed with the HCB diet exhibited significantly the highest cumulative survival rate of 60% after 72 h while those fed with diet C and HC exhibited lower survival rates of 33% and 40%, respectively, and were not significantly different from each other. In conclusion, benfotiamine enhances attractability of the feed, growth performance and immune response against ammonia toxicity at the level of 0.2 g kg-1.

The present study aimed to determine whether or not combining Quillaja saponin (QS) and kappa-carrageenan (KC) as feed supplements could have additive or synergistic effect as growth-promoters and/or immune enhancers against hyposalinity stress in Penaeus monodon post larvae. Three separate experiments were done: (a) a random three days attractability test; (b) a 30-day feeding trial to determine optimal inclusion of combined QS+KC; and (3) a 24 h acute hyposalinity stress test following 30-day feeding five experimental diets. Attractability results showed that the QS+KC very briefly attracted the shrimps for 2 min (p<0.05) but became non-significant after longer periods. In the feeding trial, 5 experimental diets containing graded levels of QS+KC (1:1), namely, 0.0, 0.2, 0.4, 0.6, and 0.8 g.kg(-1) were fed to groups of shrimps. Results showed that the final average body weight (FABW), weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR) values of shrimps in the supplemented groups were significantly better than those of the control group; the values of those in 0.2 and 0.8 g.kg(-1) QS+KC groups were not significantly different from those of the control group. Feed intake (FI) and protein efficiency ratio (PER) values were not affected by the supplementation (p>0.05). Optimal inclusion level of dietary QS+KC was determined to be 0.4 g.kg(-1). After the feeding trial, shrimps were transferred from 24 ppt salinity media to 2 ppt. All QS+KC-fed groups exhibited significantly lower cumulative mortality rate than that of the 0.0 QS+KC group (p<0.05). The determined level of QS+KC that elicited the lowest cumulative mortality rate was 0.5 g.kg(-1). In conclusion, the study demonstrated that the combined dietary Quillaja saponin and kappa carrageenan acted synergistically in the promotion of growth and feed efficiency and in the enhancement of immune response against acute hyposalinity stress.

There is a need to evaluate and choose a possible population source of the threatened catfish Clarias macrocephalus for possible reintroduction into aquaculture. Identifying gene transcription profiles that provide fitness benefits in specific environments would promote more effective species reintroduction and conservation practices. In this study, comparison of hepatic transcriptome profiles was made in terms of expression patterns of various growth-, immune- and reproduction-related genes of two Clarias macrocephalus strains from Cagayan (CmC) and Agusan del Sur (CmA), located in the Northern and Southern Philippines, respectively. RNA sequencing results showed that there were 13,138 differentially expressed genes (DEGs) identified in CmA vs. CmC, of which 6,795 DEGs exhibited significant upregulation while 6,343 DEGs displayed significant downregulation. From this pool of DEGs, numerous immune- (complements C3, C4, C7), growth- (glutamine synthetase, GLUL; glycogen synthase, GYS; elongation of very long chain fatty acids protein 6, ELOVL6, lipoprotein lipase, LPL) and reproduction-related (vitellogenin, VTG; cytochrome p450 19b-like, CYP19b; progesterone receptor, PGR) genes were identified. Pathway enrichment analysis revealed the enrichment of the complement component and coagulation cascades, protein digestion and absorption and lipid metabolism pathways. Results of this study indicated that when reintroduction was to be done, C. macrocephalus population from Agusan Marsh is predicted to grow much faster because of up-regulated growth-related genes, to be more resistant to pathogens/environmental stressor as it manifested up-regulated immune-related genes and to reproduce better as reflected by its up-regulated reproduction-related genes than its counterpart catfish from Cagayan.

The present preliminary study investigated the effects of different levels of dietary pine pollen from Pinus tabulaeformis Carr. on the growth and efficiency performance and ammonia stress resistance of milkfish fry (Chanos chanos). After acclimation, 600 milkfish fry with average body weight of 0.02 g were stocked in 15, 50L tanks (40 fish per tank). A control diet (without pine pollen, PP) and 4 experimental diets containing various levels of PP, namely, 0, 1.3, 2.6, 3.8, and 5.1 g/kg were prepared and given for 60 days. At termination of the experiment, milkfish were subjected to ammonia stress. Results showed that milkfish fed diets containing various levels of pine pollen exhibited significantly higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), and better feed conversion ratio (FCR) than fish fed the control diet. Survival rates of the milkfish during the feeding trial were not significantly different among dietary treatments (p>0.05). A separate experiment was conducted in which milkfish were subjected to ammonia stress test following feeding of experimental diets for 2 weeks. Results showed that milkfish fed with diets containing 2.6 to 5.1 g/kg exhibited significantly higher survival (p<0.05) than did those fed with the control diet and with the diet containing 1.3 g/kg PP. The optimal inclusion level of pine pollen was estimated using values for SGR and FCR fitted to quadratic model to be 3.0 g/kg. The results of this study indicated that pine pollen could be used as a dietary additive for the young milkfish to enhance growth and immune response to dissolved ammonia.