Growth Hormone Relative To Stunting In Crowded Conditions

[koicluboftheair]

As we often here of how limiting the space koi fry have to grow in stunts their growth, I wonder if this is due to some biological trigger such as somatostatin that reduces the amount of growth hormone secretion in certain environmental conditions? If so, is it possible to artificially counter balance such gh inhibition by alternative chemical treatments with pituitary fragments for instance or other means? How are these sorts of considerations currently dealt with in the industry? Cysteamine is a somatostatin blocker, but I don't know to what extent it is used in the industry to increase farm yields without reducing the quality of the koi growth potential after the sale.

Growth hormone and gonadotropin secretion in the common carp (Cyprinus carpio L.): in vitro interactions of gonadotropin-releasing hormone, somatostatin, and the dopamine agonist apomorphine.

Department of Biology, Zhongshan University, Guangzhou, People's Republic of China.

The effects of salmon gonadotropin-releasing hormone (sGnRH) and the superactive agonist [D-Arg6, Pro9NEt]-sGnRH (sGnRH-A) on growth hormone (GH) and gonadotropin (GtH) release were examined using a perifusion system for pituitary fragments of the common carp (Cyprinus carpio). Perifusion of 2-min pulses of different concentrations of sGnRH or sGnRH-A stimulated a rapid and dose-dependent increase in GH release: ED50 values for sGnRH and sGnRH-A in stimulating GH release were 2.8 +/- 0.7 and 0.5 +/- 0.1 nM, respectively, indicating that the superactivity of sGnRH-A for stimulation of GtH release also applies in induction of GH release. Exposure of the pituitary fragments to 10 nM sGnRH or sGnRH-A alone resulted in increases in GH and GtH release on a similar temporal course. Apomorphine (10, 100, and 1000 nM) significantly inhibited basal and GnRH-induced GtH release in a dose-dependent manner and significantly stimulated basal GH release; however, APO did not enhance GnRH-induced GH release. Somatostatin (100 nM) significantly blocked basal release and 10 nM sGnRH- and sGnRH-A-induced GH release, but was ineffective on GtH release. Treatment with somatostatin (100 nM) in combination with apomorphine (100 nM) caused an increase in sGnRH-induced GH release compared to treatment with somatostatin alone; whereas, on GtH there was a significant decrease in basal and GnRH-induced levels, compared to treatment with somatostatin alone. These results indicate that GH release in common carp is regulated by somatostatin as GH release inhibitor. sGnRH and sGnRH-A act as GH-releasing factors; the mechanisms by which GnRH stimulates GH and GtH secretion are independent. The dopamine agonist apomorphine stimulates GH release and inhibits GtH release directly at the pituitary level.

PMID: 8094060 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Citation

[koicluboftheair]

Well I suppose the earlier studies did lead to use of Cysteamine to some extent to induce growth. I wonder if this sort of technique would be satisfactory for the hobbyist trying to grow out a GC in less than optimum pond conditions? Certainly if breeders can maximize their yields in this way hobbyists could likewise benefit?

Cysteamine-a somatostatin-inhibiting agent-induced growth hormone secretion and growth acceleration in juvenile grass carp (Ctenopharyngodon idellus)Author DONG XIAO ; LIN Hao-Ran ;

Abstract

Effects of cysteamine hydrochloride (CSH)-a somatostatin-inhibiting agent on growth hormone (GH) secretion from pituitary fragments (PF) or hypothalamus plus pituitary fragments (HPF) under static incubation conditions, serum GH, 3,5,3'-triiodothyronine (T[3]) and thyroxine (T[4]) levels, and growth in juvenile grass carp (Ctenopharyngodon idellus) were investigated. CSH (0.1, 1, and 10 mM) had no influences on GH release from PF after 1 and 6 h incubation, but was effective in stimulating GH release from HPF in a dose-dependent manner after 1 and 6h incubation. Moreover, prolonged treatment of HPF with CSH decreased the magnitude of enhancement of GH levels in culture medium. CSH and neuropeptides [e.g., human GH-releasing hormone (hGHRH, 100 nM), luteinizing hormone-releasing hormone analog (LHRH-A, [D-Trp[6],Pro[9]]LHRH, 100nM)], or salmon gonadotropin-releasing hormone analogue (sGnRH-A, [D-Ala[6],Pro[9]]LHRH, 100 nM), alone and in combination during static incubation stimulated GH release from HPF after 1 h incubation; in addition, there was an additive, not a synergistic effect of CSH and neuropeptides on stimulation of GH release. Administration of CSH (2.5 mg/g diet) in combination with LHRH-A (5 μg/g diet) in diet twice daily for 8 weeks resulted in higher serum GH, T[3], and T[4] levels, ratio of RNA/DNA in muscle, food conversion efficiency, and growth rate than CSH or LHRH-A alone. At trial termination, significant decreases in condition factors and body lipid levels were observed in fish fed with CSH and/or LHRH-A. No significant differences were recorded for viscero-somatic index, hepato-somatic index, and percent body moisture and protein in muscle. These findings, taken as a whole, strongly suggest that the action of CSH stimulating GH release in vitro appears to be mediated through hypothalamic pathways and dietary delivery of CSH directly or indirectly stimulates endogenous GH, T[3], and T[4] secretion, and subsequently leads to a increase in growth rate in grass carp.Revue / Journal Title

General and comparative endocrinology (Gen. comp. endocrinol.) ISSN 0016-6480 CODEN GCENA5
http://cat.inist.fr/?aModele=afficheN&cpsidt=15337401

[MikeM]

I think water changes and improved husbandry would be much easier.

[koicluboftheair]

Quote: Originally Posted by MikeM I think water changes and improved husbandry would be much easier.

Regarding recommendations for average hobbyists I generally agree, but where aquaculturists, and koi farmers might find it beneficial to use and might be using such chemistry I find it an interesting consideration. As with use of pro-biotics in food and now sprays-on types that are supposedly more effective in the case of AndersonBio's Koibiotic it seems hobbyists can get some tips from the commercial side of the biz.

The product is already available for import and as there are numerous producers of domestic feeds for one's own farm use along with wholesale/retail consider the possibilities.

It seems quite a few tons of it are sold under the name "Shengzhangan."

"Trade Lead Description:
Shengzhangan gives exhaustion effect on samatostain in animals including poultry, livestock and aquatia animal. This leads to prominent enhancement of Growth hormone (GH) in animals, improved utilization of the feed, and greater weight increase.
Shengzhangan introduced the newly “double embedment” technique, the outer envelope composed by annulated macromolecule while the inner envelope composed by soluble resin. This technique eliminated the side-effect of cysteamine, and accelerated the absorbability of the active ingredient in intestinal."
http://market.tradeholding.com/defau..._shengzhangan/


"Cysteamine Hydrochloride( Cysteamine HCL )
Hangzhou Xiaoshan Qianjin Chemical Co.,Ltd."
http://www.fuzing.com/vli/0007061fc2...ysteamine-HCL-

[koicluboftheair]

Quote: Originally Posted by MikeM I think water changes and improved husbandry would be much easier.

I wonder if this would help with improving yields on wild spawns we might raise in the backyard in small system that typically yield stunted specimens? It could be a good tool for selling bigger fish at club auctions if not actually producing more show fish. Obviously most of the industry is geared toward quantity not quality.

[koiczar]

Quote: Originally Posted by MikeM I think water changes and improved husbandry would be much easier.

Grat response Mike. Next thing we'll be hearing about is how to dye the black eyes on sanke blue LOL

Or maybe better yet, Frankenstein may not be a part of history if some of these idiots have their say!!

Mike P

[koicluboftheair]

Quote: Originally Posted by koiczar Grat response Mike. Next thing we'll be hearing about is how to dye the black eyes on sanke blue LOL Or maybe better yet, Frankenstein may not be a part of history if some of these idiots have their say!! Mike P

Mike,
Surely you aren't saying growth hormone use isn't being used in commercial aquaculture; or more specifically koi-aquaculture? Heck, how do we explain commercial breeders in this country being able to raise far more un-stunted fish in a small area than you could at home? If there is a chemical trigger in the koi that in crowded conditions where space to grow and available food is an issue it would seem stunting would have survival value. And where that chemical response to stop production of gh can be prevented then the growth would continue and produce more valuable fish. Pretty simple I think if the science is good.

[Gail]

http://www.worldfishcenter.org/Pubs/...apter%2015.PDF


I like Mikes answer.

[koicluboftheair]

Genetic engineering seems to be another tool of the commercial aquaculturist toward maintenance and manipulation of growth hormone release in the species as well:

Genetic engineering and transgenesis
Investations on a few candidate genes have been initiated and/or in progress. Most noteworthy is the work on the effect of growth hormone (HG) engineered for expression using various promoters, on common carp and gilthead seabream growth. Moav (Dept. of Zoology, Tel Aviv university) and coworkers have demonstrated 20% growth improvement in transgenic carp reare din experimental earth ponds. Current efforts are aimed at constructing new expression vectors to improve efficiency of producing transgenic fish.
http://www.worldfishcenter.org/Pubs/...apter%2015.PDF

[KoiCop]

Quote: Originally Posted by Gail I like Mikes answer.

I agree.

Some folks, though, are always on the lookout for a way to game the system rather than taking the time to do it right and play it straight -- think Barry Bonds and steroid juicing narcissistic bodybuilders, I guess. More's the pity.