Periphyton Technology Enhances Growth Performance and Delays Prolific Breeding of Nile Tilapia, Oreochromis niloticus (Linnaeus, 1758), Juveniles

This study evaluated the effect of periphyton technology (PPT) on the growth performance and breeding schedule of Oreochromis niloticus (Linnaeus, 1758) juveniles. Six ponds, each measuring 81 m2 were used for the study. The ponds were applied with agricultural lime at a rate of 4 g.m-2, and fertilised using chicken manure to facilitate primary productivity. The PPT ponds were fitted with two-metre-long eucalyptus poles of 5 cm diameter placed at 50 cm intervals with the regular addition of molasses as a carbon source. Tilapia juveniles were stocked at a density of 3 fish.m-2 in all ponds and fed on a commercial diet of 20 % crude protein (CP) twice daily at 3 % body weight. Fish were sampled weekly for growth and survival data and bi-weekly for fecundity estimates. The PPT-ponds registered significantly higher survival rate (97.50 ± 0.35 %), mean weight (150.69 ± 0.99 g), specific growth rate (SGR) (2.75 ± 0.01), and feed conversion ratio (FCR) (1.29 ± 0.01), than the control ponds, which registered survival (91.15 ± 0.88 %), mean weight (99.23 ± 0.96 g), SGR (2.29 ± 0.00), and FCR (1.58 ± 0.01). There was significantly higher fecundity in the PPT-ponds (2.28 ± 0.09 g.fish-1) than control (1.74 ± 0.06 g.fish-1), with prolific spawning starting 4 weeks earlier in the control ponds than in the PPT-ponds. This study demonstrated the potential of PPT for enhancing tilapia growth while delaying prolific breeding behaviour. Further studies should explore PPT in replacing synthetic hormones for sex-reversal of tilapia fry in hatcheries.

Use of Dietary Phytochemicals as control for Excessive Breeding in Nile Tilapia (Oreochromis niloticus): A review

Human population has continued to increase unabatedly with its attendant demands on food in order to ease the difficulties of malnutrition and starvation. This continuous rise in population has clearly indicated that the conventional forms of livestock production and captured fisheries will not be sufficient to solve the problem of high protein demands. Aquaculture remains the best option that can bridge the wide gap between human protein demands and domestic production through the culture of fish species like Nile Tilapia (Oreochromis niloticus). Oreochromis niloticus is one of the most cultured finfish, due to its acceptability as food, fast growth, availability for farmers, ability to breed in captivity, resistance to diseases and harsh environmental conditions. Despite all these outstanding characteristics, there is still high level of apathy in commercial production of Nile Tilapia, due to its precocious maturity and uncontrolled breeding, which results in overpopulation of ponds, stunted growth and low commercial value. To mitigate this challenge, the use of synthetic hormones such as 17α-methyl testosterone has been developed to masculinize female tilapia present in a pond, thereby allowing the production of marketable sized fish since the male grows faster than the female. Though, the use of synthetic hormones has helped in some ways, but the negative effects have necessitated farmers to seek alternatives that are environmental friendly and safe for consumers. Dietary phytochemicals have been established to be good alternatives and their use is now gaining global acceptance. Dietary phytochemicals are bioactive compounds commonly found in plant-based diets such as fruits, vegetables, grains and teas. Dietary phytochemicals when administered to newly hatched tilapia species, influences the undifferentiated gonadal tissue of generic females to develop testicular tissue, thus functioning reproductively as males. Some of these phytochemicals such as Flavonoids, Saponins, Phenolics and Alkaloids are found in plants like Carica papaya seeds, Azadirachta indica, and Mucuna pruriens. The usefulness of these phytochemicals is based on their ability to influence sex reversal in Oreochromis niloticus, cost effect, easily accessible especially by small scale fish farmers, simple to apply, and being safe for both human and the environment since they are more biodegradable than synthetic hormones.

A Sensitive, Robust Method for Determining nNatural and Synthetic Hormones in Surface and Waste Waters by Continuous Solid Phase Extraction–Gas Chromatography–Mass Spectrometry

One recent trend in Analytical Chemistry is to develop economical, fast green methods using minimal amounts of solvents to determine a variety of analytes spanning a wide range of physicochemical properties. In this work, we developed a sensitive, selective method for the simultaneous determination of thirteen natural and synthetic hormones present at the nanogram-per-liter level in various types of water by using continuous solid phase extraction in combination with gas chromatography and mass spectrometry (GC–MS). The target analytes were preferentially sorbed on an Oasis HLB sorbent column and eluted with acetone for derivatization with a mixture of N,O-bis(trimethylsilyl) trifluoroacetamide and trimethylchlorosilane in a household microwave oven at 200 W for 4 min. Under optimum conditions, the ensuing method exhibited good linearity (r ≥ 0.998), good precision (RSD ≤ 7%), high recoveries (92–103%) and low detection limits (0.01–0.3 ng L− 1). The method outperforms existing alternatives in robustness, sensitivity, throughput, flexibility —it allows both estrogens, progestogens and androgens to be determined simultaneously— and compliance with the principles of Green Chemistry. It was successfully used to analyze various types of water samples (mineral, tap, well, pond, swimming pool, river and waste) that were found to contain four estrogens (estrone, 17β-estradiol, 17α-ethinylestradiol and hexestrol), two progestogens (testosterone, dihydrotestosterone) and one progestogen (progesterone) at concentrations ranging from 3.0 to 110 ng L− 1.

A Review on Environmental Contaminants-Related Fertility Threat in Male Fishes: Effects and Possible Mechanisms of Action Learned from Wildlife and Laboratory Studies

Increasing global rates of diminished fertility in males has been suggested to be associated with exposure to environmental contaminants (ECs). The aquatic environments are the final repository of ECs. As the reproductive system is conserved in vertebrates, studies on the effects of ECs on fertility endpoints in fishes provide us with valuable information to establish biomarkers in risk assessment of ECs, and to understand the ECs-related fertility threat. The aim of the present review was to evaluate associations between ECs and fertility determinants to better understand ECs-related male fertility threat in male fishes. Wildlife studies show that the reproductive system has been affected in fishes sampled from the polluted aquatic environment. The laboratory studies show the potency of ECs including natural and synthetic hormones, alkylphenols, bisphenols, plasticizers, pesticides, pharmaceutical, alkylating, and organotin agents to affect fertility determinants, resulting in diminished fertility at environmentally relevant concentrations. Both wildlife and laboratory studies reveal that ECs adverse effects on male fertility are associated with a decrease in sperm production, damage to sperm morphology, alternations in sperm genome, and decrease in sperm motility kinetics. The efficiency of ECs to affect sperm quality and male fertility highly depends on the concentration of the contaminants and the duration of exposure. Our review highlights that the number of contaminants examined over fertility tests are much lower than the number of contaminants detected in our environment. The ECs effects on fertility are largely unknown when fishes are exposed to the contaminants at early developmental stages. The review suggests the urgent need to examine ECs effects on male fertility when a fish is exposed at different developmental stages in a single or combination protocol. The ECs effects on the sperm genome are largely unknown to understand ECs-related inheritance of reproductive disorders transmitted to the progeny. To elucidate modes of action of ECs on sperm motility, it is needed to study functional morphology of the motility apparatus and to investigate ECs-disrupted motility signaling.

Comparative Study on the Natural and Synthetic Hormones ofClarias gariepinus Broodstock

The study was carried out for six (6) weeks at the Department of Fisheries Teaching and Research farm, Modibbo Adama University, Yola, to compare the reproductive performance of Clarias gariepinus using synthetic (ovaprim) and natural (C. gariepinus pituitary extract) hormones . At the end of the feeding trial, the fecundity, percentage fertilization, hatchability, and survival rates of the hatchlings were estimated using standard procedure. The hatchlings were further raised for six weeks and the increase in weight was determined. The results showed that female broodstock injected with C. gariepinus pituitary extract (CgPE) had a higher fecundity (124,000) while the female injected with Ovaprim had 65,000 eggs. The weight of the testes significantly differed (p<0.05) across the treatments, the right lobe weighed 1.63g while the left lobe weighed 1.98g . Subsequently, a higher fertilization rate was recorded in CgPE (91.1%) while Ovaprim had 85.55% . However, Ovaprim had a higher percentage hatchability of 82.93% while CgPE had 82.73% . At the end of the six (6) weeks feeding period, the survival rate was higher in the fish treated with CgPE (82.31%) while the fish injected with Ovaprim had 79.68% . The research exposed the efficacy of using CgPE in the absence of synthetic hormone, CgPE is a preferred substitute that Hatchery managers can utilize for fingerlings production.

Natural biostimulants as upscale substitutes to synthetic hormones for boosting tomato yield and fruits quality

Natural biostimulants are one of the most promising and eco-sustainable technologies, which can improve the qualitative and productive attributes of horticultural crops. The positive effects of their application derive from their “signaling role” as elicitors of auxin- and gibberellin-like activity, thus constituting a valid alternative to synthetic hormones. Our research aimed to assess the efficacy of a plant extract (Heptamin®) and a bacterial culture filtrate (Capxium®), both rich in natural auxins, and of a synthetic auxin (Auxyger® LG) on the quantitative and qualitative performance, as well as on the economic returns of greenhouse table tomato (Solanum lycopersicum L. cv. Pitagora). The application of plant extract increased the marketable yield (+25.8%), firmness (+25.7%), and fruit lycopene content (+42.5%) compared to the untreated control. In particular, natural biostimulants outperformed synthetic auxin by inducing higher fruit weight (13.1%) and marketable yield (16.2%). On the other hand, no significant differences were recorded as a result of the treatments regarding total soluble solids, pH, and titratable acidity of the fruit juice. Our results suggest that plant biostimulants with auxin-like activity are an excellent tool for boosting tomato production and fruit quality in an eco-sustainable approach. Finally, economic analysis revealed that the application of natural biostimulants resulted in overall higher profitability

Questions of control of hormone content in fish and other aquatic organisms (metaanalysis)

Between 1995 and 2018, the production of fish and fishery products using feed increased from 12 to 54.3 million tons. In the cultivation of such products in many countries, hormones are widely used as growth stimulants to increase the efficiency of feed conversion for the purpose of sex reversal, as well as for artificial reproduction. Hormones, especially their synthetic forms, are poorly metabolized in the marine organisms, which leads to their accumulation in the food matrix. When they enter the human body, they are capable of accumulation in tissues, affect the endocrine system and can cause the development of a number of metabolic disorders. The possibility of a carcinogenic effect of hormones has been proven. The data presented substantiate the need to control the content of hormones in fish and fish products, develop highly sensitive methods for their detection, establish a list of controlled hormones and hormone-like drugs and safety regulations for food products produced with their use. The most sensitive and accurate method in this case is the HPLC-MS/MS method. We believe that for natural (non-synthetic hormones) and synthetic hormones, the criterion for their absence in the sample should be the sensitivity threshold of the used research method (at least 20 ng/kg).

Ikan dan Krustasea: Aplikasi Bahan Alam Untuk Pertumbuhan dan Reproduksi

Aquaculture is a solution in providing animal nutrition for humans. Capture fishing and aquaculture are the two main sources of fisheries production in Indonesia. Indonesia is one of the world's top exporters of fisheries products. Fish have a unique growth pattern. Fish use available nutrients for the reproductive process as they get older, but there is still a positive contribution to growth. The requirements for optimum temperature, feed, and growth period for juvenile and adult fish may be different. Reproduction in organism, including aquatic animals, is controlled by hormones. Hormones involved in reproduction such as steroids, FSH, LH, estradiol etc. In aquaculture, the increase in growth and reproduction in fish and crustaceans uses a lot of synthetic hormones, which there are still many weaknesses. The use of natural product is one of the environmentally sustainable options for increasing growth and reproduction. There have been many applications of natural products that have been able to improve growth and reproduction, such as the use of celery, Karamunting, Katuk, Paku Uban and Turmeric. Some of the references to this book are the result of the author's research that has been published in various national and international journals

Comparative study on spawning success of paradise fish (Macropodus opercularis) using synthetic hormone and natural simulation

Synthetic hormones are widely used for induced breeding with significant successes. This study compared spawning successes in paradise fish (Macropodus opercularis) using synthetic hormone (Ovaprim) and natural simulation in glass tanks (0.3m x 0.6m). The experiment was conducted in two parts using two males and two females brood fish. The weights of the fish were between 4.0 and 5.0g for the males and 5.0 and 6.0g for the females. For the induced spawning, Ovaprim was injected intramuscularly according to the fish body weight after which they were left to spawn. The group on natural spawning were not induced by any hormone. Hatching of the eggs occurred within 48 hours at a temperature of 28.80C. Total number of eggs obtained by artificial and natural breeding were 430 and 322eggs respectively. Percentage fertilization in artificial breeding was 63.26% while 41.93% was recorded in natural breeding. Fry were raised on compounded diet for 6 weeks. Results showed that artificially bred fish had a higher mean weight gain (2.31 g) and survival rate (48.17%) than those from natural breeding having 2.10 g and 44.26% respectively. The results suggest that artificial breeding using synthetic hormone (Ovaprim) yielded better spawning success and survival rate than natural process. Keywords: Paradise fish, natural breeding, hormone, fertilization, survival