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The pituitary and thyroid hormones have been known as the most important biochemical substances, which are responsible for metamorphic differentiation during larval development along with many physiological process of prime importance during periods too (Belsare et al., 1966) The maintenance of adequate balance of pituitary and thyroid hormone levels are important prerequisite for proper management of reproductive biology, development, growth and it may prove important regulating factor. The effect of thyroxine hormone treatment along with the pituitary in a combined form on the post- embryonic development of Cirrhina mrigala is not yet fully known and needs further investigation. With this view point in the present communication, an effort has been made to work out the optimum combined dose of pituitary and thyroid hormones, which could be able to effect some aspects of post-embryonic development in a positive direction.

Some of the important studies on the said field are from Hoar et al. (1955); Lostrh et al. (1958); Scow (1959); Sneed et al. (1961); Nicall et al. (1965); Belsare et al. (1966);Yamazaki (1976); Holder et al. (1980); Miwa et al. (1985); Tay et al. (1997) ;Nayak et al. (2000); MacKenzie DS, Jones RA, Miller TC. (2009); Maugars G, Dufour S, Cohen- Tannoudji J, Querat B. (2014); Yu J, Fu Y, Shi Z. (2017);Ganzha EV, Pavlov ED (2019); Stepien BK, Huttner WB. (2019); Alinezhad S, Abdollahpour H, Jafari N, Falahatkar B. (2020); Blanco AM. (2020) and that of Ma Y, Ladisa C, Chang JP, Habibi HR.(2020).

The hatchlings (3-4 days old) of Cirrhina mrigala were collected from fish farm in the close vicinity of Raebareli. The hatchlings for consecutive development stages were brought to laboratory and transfer to plastic trough under observation. In each experimental trough,20 specimens were placed on the basls of proper stocking density (approximately 2fish/lit.). The physio-chemical conditions of the experimental troughs were maintained nearly natural by using sand particles, phytoplankton’s ,zoo and hydrilla plants. Hitachi readymade food pellets in equal quantity were also given at regular intervals to all the experimental larvae. The combined (pituitary and thyroid hormone) doses of 1 + 80 mg/lit., 2.2 +105 mg/lit. and 3+ 130 mg/lit. concentration were prepared and one kind of dose was added in each trough. Five specimens from each kind of experiment sampled randomly and control were taken out for derivation of mean standard under different aspects of studies on post-embryonic development at successive time period viz.,4,8 and 16 days. The same findings were applied after lapses of 22 and 30 days in order to study later development stages. Morphometrical parameters of the larvae were recorded with the help of Vernier Calipers at the end of each experiment.

In each experimental trough,20 specimens were placed on the basls of proper stocking density (approximately 2fish/lit.). 

Results and Discussion

Comparing the parameters indicating in the Table-1, it can be concluded that a dose of 2.2 +105 mg/lit. proved to be the best in terms of post-embryonic development.

Table-1 Morphometry of Cirrhina mrigala (Ham.) larvae treated with combined doses of pituitary (P) and thyroid (T) hormone (mg/lit.)

Sl.No.	Morphometrical parameters (Average in mm ± S.D.)	Control	Treated experiments
		0 +0 mg/lit.	1 + 80 mg/lit.  (P + T)*	2.2+105 mg/lit.  (P + T)*	3 + 130 mg/lit.  (P + T)*
1.	Standard length	22.987±0.047	34.724±0.564	38.353±0.856	37.987±1.356
2.	Body length	13.937±0.235	23.012±1.023	26.259±1.443	26.632±1.337
3.	Head length	6.307±0.063	8.223±0.524	9.652±0.045	8.553±1.658
4.	Distance between snout and anal pore	14.982±0.658	22.895±1.325	27.524±1.023	24.032±1.241
5.	Distance between snout and anal fin base	17.077±0.061	27.082±1.025	30.012±1.432	30.421±1.245
6.	Distance between snout and dorsal fin base	13.552±0.046	22.343±0.653	23.658±1.532	23.012±0.856
7.	Height of the body at anal fin base	4.887±0.109	8.022±0.856	8.234±0.653	8.125±0.356
8.	Height of the body at dorsal fin base	6.878±0.075	10.035±0.965	10.465±0.854	9.562±1.235
9.	Mortality	Four	Six	Five	Ten

 *Pituitary and Thyroid dose.

The general Morphometrical parameters of  Cirrhina mrigala larvae revealed that at a dose of 2.2 + 105 mg/lit., standard length 38.353 mm; body length 26.259 mm; head length 9.652 mm; distance between snout and anal pore 27.524 mm; distance between snout and anal fin base 30.012 mm, distance between snout and dorsal fin base 23.658 mm, height of the body at anal fin base 8.234 mm and height of the body at dorsal fin base 10.465 mm was observed, which is significant in terms of the best dose estimated in correspondence to post embryonic development.

During early development periods it has also been observed that when morphogenesis is on its full swing, the combined pituitary and thyroid hormone dose (2.2 + 105 mg/lit.) resulted into maximum increment in standard body length. Survival percentage was maximum in control, which gradually decreased at 1 + 80 mg/lit., 2.2 + 105 mg/lit. and 3 + 130 mg/lit. dose treatments (Table-1). Therefore it can be inferred that 2.2 + 105 mg/lit. dose seems to be the best effective dose in respect to post-embryonic development and low mortality of Cirrhina mrigala larvae.

1. Belsare., D.K.,Zagar, V.N. and Vermar,S.M. 1966. The effect of thiourea and thyroxine on the developing larvae of Channa punvtatus (Bloch). Zool.Polom. 16:144-154 2. Hoar, V.S., Yeenleside, M.H. and Goo.all R.C. 1955. The effect of thyroxine and gonadal steroids on the activity of salmon and gold fish. Can. J. Zool. 33:428-439 3. Holder A.T., Walls, M. Biggs, P. and Precce, M.A. 1980. Effect of growth hormone, prolactine and thyroxine on the body weight-somatomedin-like activity in vivo sulphation of cartilage in hypopituitary dwarf mice. J. Endocrinol. 84: 35-47. 4. Lostroh, A.J. and Choh, H.L. 1958. Effects of growth hormone and thyroxine on body weight of hypopasectomized C3H mice, Gen. Comp. Endocrinol. 62: 484-491. 5. Miwa, S. and Iaui,Y. 1985. Effect of L-thyroxine and bovine growth hormone on smoltification of a mago-salmon, Onchorhynchus rhodurus. Gen.Cam. Endocrino. 58:436-442. 6. Nayak, P.K., Mishra, T.K. and Mishra, J. 2000. Combined application of cortisol and thyroxine in the culture of larvae of freshwater catfish, Heteropneustes fossilis. J. Aquacult. Trop. 15: 323-328 7. Nicall,C.S., Bem, H.A., Dunlop and et.al. R.C. 1965, Prolactin, growth hormone, thyroxine and growth in Tadpoles on Rana catesbeiana. Amer. Zool. 5:738-739. 8. Scow,R.O.1959. Effect of growth hormone and thyroxine on growth and chemical composition of muscle, bone and other tissue in throidectomizea rats. Am. J. Physiol. 196: 859-865. 9. Sneed K.E. and Dupree, H.P. 1961. The effect of thyroid stimulating hormone combined with gonadotropic hormones on the ovulation of goldfish and green sunfish. Preg. Fish Culturist. 23: 179-182. 10. Tay,H.C.; Young, A.N.; Goh, J.; Him. H.S.; Chao, T.M.; Chou, R. and Lam, T.J. 1997. Effects of treatment of eggs with triiodothyroxine and cortisol on larvae morphology and survival in the greasy grouper Aquacult. International. 54 : 189-195. 11. Yamazaki, F. 1976. Application of hormone in fish culture. J. Fish Res. Bd. Can. 33 : 948-958. 12. MacKenzie DS, Jones RA, Miller TC. Thyrotropin in teleost fish. Gen Comp. Endocrinol (2009) 161(1) : 83-9. Doi: 10.1016/j.ygcen.2008.12.010 13. Maugars G, Dufour S, Cohen- Tannoudji J, Querat B. Multiple thyrotropin β- subunit and thyrotropin receptor- related genes arose during vertebrate evolution. PloS One (2014) 9(11): e111361-e. doi:10.1371/journal.pone.0111361 14. Yu J, Fu Y, Shi Z. Coordinated expression and regulation of deiodinases and thyroid hormone receptors during metamorphosis in the Japanese flounder (Paralichthys olivaceus). Fish Physiol Biochem (2017) 43(2):321–36. doi: 10.1007/s10695-016-0289-0 15. Ganzha EV, Pavlov ED. Diurnal dynamics of thyroid and sex steroid hormones in the blood of rainbow trout juveniles. Inland Water Biol (2019) 12(3):333–6. doi: 10.1134/S1995082919030064 16. Stepien BK, Huttner WB. Transport, metabolism, and function of thyroid hormones in the developing mammalian brain. Front Endocrinol (2019) 10:1–16. doi: 10.3389/fendo.2019.00209 17. Alinezhad S, Abdollahpour H, Jafari N, Falahatkar B. Effects of thyroxine immersion on sterlet sturgeon (Acipenser ruthenus) embryos and larvae: Variations in thyroid hormone levels during development. Aquaculture (2020) 519:734745–. doi: 10.1016/j.aquaculture.2019.734745 18. Blanco AM. Hypothalamic– and pituitary–derived growth and reproductive hormones and the control of energy balance in fish. Gen Comp Endocrinol (2020) 287:113322. doi: 10.1016/j.ygcen.2019.113322. 19. Ma Y, Ladisa C, Chang JP, Habibi HR. Seasonal related multifactorial control of pituitary gonadotropin and growth hormone in female goldfish: Influences of neuropeptides and thyroid hormone. Front Endocrinol (2020) 11:175. doi: 10.3389/fendo.2020.00175