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VETERINARSKI ARHIV = 69 (1), 7-15,=20 1999

ISSN 1331-8055 = Online
ISSN=20 0372-5480 Printed in Croatia





Non-stripping = induced spawning and=20 double spawning
of grass carp in a hatchery system
with = foliage-free brood=20 diet

Suresh Chandra = Rath*, Satya Dev=20 Gupta,
and Subrata Dasgupta

Central Institute of = Freshwater=20 Aquaculture, Kausalyaganga, Bhubaneswar, India =





* Contact address:
Dr. = Suresh=20 Chandra Rath,
Central Institute of Freshwater Aquaculture, = Kausalyaganga,=20 Bhubaneswar, 751002 (Orissa) India,
Phone: 91 674 46 34 21; Fax: 91 = 674 46=20 34 07

RATH, S. C., S. D. GUPTA, = S. DASGUPTA:=20 Non-stripping induced spawning and double spawning of grass carp in a = hatchery=20 system with foliage-free brood diet. Vet. arhiv 69, 7-15, 1999. =

ABSTRACT =

Grass carp, = (Ctenopharyngodon=20 idella (Val.)) could be induced-bred without stripping, by brood = diet=20 manipulation and improved hatchery management practices. Broods reared = on a=20 foliage-free formulated diet (soybean cake, groundnut oil cake, rice = bran and=20 fish meal) were induced-bred and compared with the breeding response of = the same=20 carp, fed with aquatic submerged weed, (Hydrilla = verticillata)=20 ad libitum. The non-stripping breeding response on the = non-foliage diet=20 (NFD) group was 82.2% and over 20.0% response of the brood reared in = foliage=20 diet (FD). Average fecundity, percentage of fertilisation, and spawn = recovery=20 rate of NFD group were recorded as 0.90=B10.15=D7105 vs.=20 0.47=B10.13=D7105; 89.6=B15.33 vs. 68.75=B123.1 and = 0.76=B10.13=D7105=20 vs. 0.25=B10.08=D7105 respectively. Broods of the NFD group = could be bred=20 twice and produced spawn at 0.45=B10.11=D7105 per kg body = mass within a=20 time gap of 70 days between two successive breedings. Non-stripping = induced=20 breeding of grass carp is facilitated with mild water current (2-3 m per = sec.)=20 and less water depth (0.5-0.6 m) in a single inlet spawning pool. =

Key words: grass = carp,=20 Ctenpharyngodon idella (Val.), non-foliage diet, foliage diet,=20 Hydrilla verticillata, non-stripping spawning, double = breeding=20


Introduction =

The grass carp = (Ctenopharyngodon=20 idella) is basically an aquatic weed feeder. It grows luxuriantly on = aquatic=20 weed and has received considerable attention for its instrumental role = in the=20 biological control of nuisance vegetation. This carp can grow up to 2.5 = kg=20 within a period of six months in a polyculture system (SINHA et al., = 1973). This=20 carp has been introduced world wide from its natural habitats in eastern = China=20 and the former USSR (SHIREMAN and SMITH, 1983). The rationale of = introducing=20 grass carp is to control weeds in an aquatic system and to increase fish = production. As with many other major carp species, the grass carp would = not=20 breed spontaneously in the confined waters of culture ponds, and needing = hormone=20 induction for artificial propagation (LIN, 1965; STANLEY, 1976). The = first=20 induced breeding of grass carp was reported in China in 1960 (KURONUMA, = 1968),=20 followed by the USSR in 1961 (VERIGIN, 1963; VINOGRADOV, 1968). The = successful=20 induced breeding of grass carp introduced into new environments have = been=20 reported during last few decades: Cuttack, India (ALIKUNHI et al., = 1962);=20 Autburn, USA (JEFFREY, 1970); Koncanica, Croatia (FIJAN and VOJTA, = 1969); Nepal=20 (WOYNAROVICH, 1972); Netal, South Africa (PIKE, 1974). Induced breeding = of grass=20 carp by hand-stripping is a world wide practice after KONARDT (1968) of = the=20 USSR. ROTTMANN and SHIREMAN (1979) analysed the problem associated with = hand=20 stripping and dry fertilisation as, (I) inconsistent spawning success = due to=20 improper timing of stripping, (II) poor survival of spent brood due to = stripping=20 stress, (III) excessive requirement. Spawning stress could be minimised = by use=20 of anaesthesia prior to spawning (JEFFREY, 1970; BAILEY and BOYD, 1971, = 1973).=20

SHIREMAN and SMITH (1983) = initiated an=20 investigation into non-stripping spawning and wet fertilisation, which = can=20 reduce brood damage and improve the spawning quality with higher = fertilisation=20 as a potential advantage over stripping. Sporadic success on the = non-stripping=20 induced breeding of grass carp has been recorded in ponds, hapa, tank = and pools=20 (LIN, 1965; CHAUDHURI et al., 1966, 1967; SINGH et al., 1970; TAPIADOR, = 1977;=20 ROTTMANN and SHIREMAN 1979; SELVARAJ et al., 1982; HUSSAIN, 1988; CIFA, = 1996,=20 1998). The present paper deals with the induced spawning of grass carp = without=20 stripping and double breeding in the same season. Breeding without = stripping,=20 and double breeding of grass carp, is based wholly on brood husbandry = and=20 hatchery management practices.

Materials and methods=20

Six ponds measuring 0.1 = ha each were=20 prepared following standard pond management practices (SINHA, 1972; = GUPTA et=20 al., 1988).

Experimental group =

Pond No. I was stocked = with grass carp=20 yearlings (0.4-0.5 kg each) together with four other carp species, viz. = Catla=20 catla, Labeo rohita, Cirrhinus mrigala and Hypophthalmichthys=20 molitrix in a ratio of 70:10:10:7:3, respectively. The stocking = density of=20 the above ponds was maintained at 1000 kg fish per ha. Here, grass carp = was the=20 principal brood component, other carp forming the maintenance component = of the=20 pond (RATH, 1997). These two ponds were made free from aquatic weed and = supplied=20 with a formulated non-foliage diet. Daily ration was soaked in water and = fed at=20 2-3% of their body mass. Feed was applied in several trays in the column = water=20 of the pond. Broods were reared for two years. 20-30% water of the ponds = was=20 replenished at least once in month from January to March.

Formulated diet =

The formulated = non-foliage diet (NFD)=20 contained soybean 50 kg, ground nut oil cake 25 kg, rice bran 20 kg and = fish=20 meal 5 kg in 100 kg feed. The approximate composition of the above feed = was=20 evaluated as crude protein 36.75%; crude fat 6.80%; crude fibre 14.25%; = total=20 ash 13.00%, and nitrogen free extract (NFE) 29.20%; energy was 13.62 = kJ/g.=20

Control group =

Pond Nos. III and IV were = prepared and=20 stocked with grass carp and with other carp as listed above. Grass carp = were fed=20 with Hydrilla verticillata ad libitum as a foliage diet. The = approximate=20 composition of the foliage diet was reported as: crude protein 14.1%, = crude fat=20 6.5%, ash 19.3%, crude fibre 6.9%, NFE 46.2%, and gross energy 14.99 kJ = per g in=20 93% dry matter (RAY and DAS, 1994). The water in these ponds was = replenished in=20 the same was as experimental group ponds.

Selection of brood =

Maturity status of female = broods was=20 assessed by the simple catheter system (CHAUDHURI et al., 1966). Mature = females=20 other than freshly cathetered individuals were selected for induced = breeding. An=20 equal number of males with free oozing milt showing>90% spermatocrit = value in=20 haematocrit capillaries and centrifuge (GUPTA and RATH, 1991) were = selected as=20 the male brood component for breeding. A total of 35 sets from the FD = group and=20 17 sets from the NFD group were selected for the non-stripping induced = breeding=20 experiment.

Induced breeding =

Selected broods were = transported to the=20 breeding pool of the ecohatchery (RATH and GUPTA, 1997) with water in = hammocks.=20 Care was taken to coincide the spawning time to the 28-30 oC=20 temperature range available on that day. Ovaprim (salomon GnRH and = domperidon,=20 Syndel Laboratoty, Canada) was used as the inducing hormone. Hormone=20 administered broods were released into the spawning pool. Water current = was=20 provided to the spawning pool by a single inlet system (RATH and GUPTA, = 1997)=20 neither before nor immediately after the hormone administration, but one = hour=20 before the calculated spawning time. Fish bred in the spawning pool = within nine=20 hours of hormone administration without stripping. Non-water-hardened = eggs after=20 each non-stripping breeding were collected from an egg collection = chamber,=20 estimated from its quantity and incubated in a flow-up glass jar system. =

Rearing of spent brood =

Spent broods were removed = from the=20 spawning pool soon after spawning was over and marked with vital dye = (M-procian=20 blue) following the method of KHAN et al. (1988). They were then = transported to=20 the pond site in a hammock with water and treated with 5 ppm potassium=20 permanganate solution.

Pond No. V was stocked = with the spent=20 brood of the experimental (NFD) group, and pond No. VI was stocked with = the=20 spent brood of the control (FD) group. Pond management was as described = above.=20 Some of the broods were matured for a second time and were also bred in = a=20 hatchery without stripping.

Spawning efficiency, such = as=20 non-stripping response, fecundity, fertilisation rate, spawn recovery, = was=20 recorded. The significant difference, if any, between the data of both = the=20 groups have been tested by student's t test (SNEDECOR and COCHARAN, = 1961).=20

Results =

Matured broods were = observed in the=20 ponds among>2-year age group. During this period individuals in the = NFD and=20 FD groups grew to 2.45=B10.40 kg (range, 1.8-3.2 kg, N=3D15) and = 5.02=B10.48 kg=20 (range, 4.5-6.0, N=3D15) respectively. Female broods in the NFD group = showed 88.2%=20 of non-stripping induced spawning, whereas female broods in the FD group = showed=20 20% non-stripping spawning (Table 1), 31.5% stripping and 48.5% = non-response on=20 induction. Non-responding brood females ejected water through their = genital=20 aperture on attempting stripping. Freshly cathetered females showed poor = spawning response. Spawning started within one hour of initiation of sex = play.=20 Grass carp preferred mild water current (2-3 m per sec) and less water = depth=20 (0.5-0.6 m) in the spawning pool for non-stripping induced breeding. On = peak=20 estruation small, slender and healthy brood showed better coiling = courtship over=20 fatty and heavy broods. It was observed that the fatty brood of the FD = group=20 came closer to each other and expelled their gametes without proper = coiling,=20 even at peak estruation. Fecundity and spawn recovery per unit body mass = of the=20 female was found to be greater in the NFD group compared to FD = individuals=20 (Table 1). The NFD brood could be bred for a second time with a = fecundity of=20 0.66=B10.15=D7105 vs. 90=B10.15=D7105 of the first = spawning of its=20 own (Table 1). Time gap between first and second spawning was recorded = as 70=20 days. Percentage of fertilisation was also observed more in NFD spawning = instances (Table 1).

Table 1. Non-stripping = spawning=20 response of grass carp (Ctenopharyngodon idella) reared on = foliage diet=20 (FD) and non-foliage diet (NFD)

Diet =

Breeding =

No. of females = taken=20

No. of female = bred=20

% of breeding = response=20

Egg produced = 105/kg=20 body mass=B1SD (range)

% of = fertilisation=B1SD (range)=20

Spawn = recovery=B1SD (range)=20 105/kg body mass

FD =

1st =

35 =

7 =

20.0 =

0.47=B10.13
(0.3-0.7)=20

68.75=B123.1
(33-90)=20

0.25=B10.08
(0.15-0.40)=20

2nd =

9 =

- =

- =

- =

- =

- =

NFD =

1st =

17 =

15 =

88.2 =

0.90=B10.15
(0.6-1.1)=20

89.6=B15.33
(74-96)=20

0.76=B10.13
(0.50-0.95)=20

2nd =

7 =

4 =

57.1 =

0.66=B10.15
(0.5-0.85)=20

82.75=B16.80
(76-92)=20

0.45=B10.11
(0.35-0.95)=20

Discussion =

On a readily available = foliage diet,=20 grass carp can feed 100%-150% of their body mass equivalent per day = (ALIKUNHI=20 and SUKUMARAN, 1965; CHAUDHURI et al., 1975; SINHA and SAHA, 1980; = TRIPATHI and=20 MISHRA, 1986; ARVINDAKSHAN et al., 1996; SINGH and BOSE, 1997) have = recorded a=20 good somatic growth of grass carp (1.8-2.5 kg) within a one-year period = in a=20 composite culture system by extra foliage diet. SINHA et al. (1973) also = observed growth as high as 2.5 kg in a period of six months, while when = fed=20 ad libitum with Hydrilla verticillata. LIN (1965) opined = that=20 grass carp grows rapidly and accummulates fat with adipose tissue in = vegetation=20 rich ponds. He further commented that such growth acts adversely on = gonadal=20 maturity and spawning. CHEN et al. (1969) reported that exclusive = feeding on=20 Hydrilla could cause extensive mesenteric fat accumulation (even = more=20 than 6% of the body mass) and can have a negative on gonadal maturation = and=20 breeding. The present study supports this observation. FD broods have = shown only=20 51.5% breeding response (including 31.5% hand stripping) over 88.2% of=20 non-stripping breeding of the NFD group. Protein content of the NFD diet = is=20 evaluated as 36.75% vs. 14% of FD, and may be one of the factors = involved in the=20 above breeding responses. Low fecundity is obvious in the FD group due = to huge=20 somatic growth, and thus the fecundity difference is highly significant = between=20 both groups (P<0.01). The inconsistent and low fertilisation rate of = the FD=20 group (Table 1) may be due to improper coiling courtship which might = have=20 reduced the chances of easy access of male and female gametes. SINGH et = al.=20 (1970) recorded 3.6% success of non-stripping induced breeding (out of = 55=20 female, 9 bred by hand stripping, and 2 bred by non-stripping). = CHAUDHURI et al.=20 (1967) reported 57.8% success of non-stripping induced spawning in a = hapa=20 breeding system (11 bred out of 19). In both cases the body mass of the = female=20 brood was limited to 1.5 kg. The present study reveals that the lower = body mass=20 gives better breeding response and that NFD broods are obviously of = lesser body=20 mass than those of the FD brood. LIN (1965) expressed that a sick = spawner always=20 fail to spawn irrespective of hormone and ripeness of the gonad. = Experienced has=20 shown that freshly cathetered females produce poor spawning results. = Despite=20 their limited success, ROTTMANN and SHIREMAN (1979) stressed the several = advantages of non-stripping induced spawning in a circular pool system.=20 Undoubtedly, the circular hatchery system and its improved management = (RATH and=20 GUPTA, 1997) facilitated the above breeding programme. It is observed = that grass=20 carp preferred slow water current (2-3 m per sec.) and less water depth = (0.5-0.6=20 m) for effective non-stripping spawning than that of Indian major carps. = Multiple breeding in carp is a new avenue to enhance seed production, = given=20 limited resources. BHOWMICK et al. (1977) reported two spawnings of = Indian major=20 carp by hypophysation under normal pond conditions. GUPTA et al. (1995) = could=20 breed Catla catla as many as four times, wholly based on an = improved=20 brood farming system. They have reported the time gap between two = successive=20 breedings as 30-60 days. HICKLING (1967) presents evidence of two of his = Malaysian grass carp brood which ovulated in May having been ripe again = in July=20 and September respectively. Presently, grass carp could be bred four = times,=20 based on non-foliage diet with a time gap of 70 days between two = successive=20 breedings. At this juncture we are unable to comment further, except to = report=20 on the non-stripping spawning efficacy of the NFD group, unless a = standard=20 balanced diet is formulated. Work in this regard is in progress. =

Conclusion =

From the above study it = appears that=20 non-foliage diet and improved hatchery management practices facilitate = the=20 non-stripping induced spawning of grass carp to promote seed production. =

Acknowledgements
The = authors are=20 grateful to Dr. S. Ayyappan, Director of the Central Institute of = Freshwater=20 Aquaculture, for his keen interest and for providing facilities to = execute this=20 work. Thanks are due to Dr. C. S. Purushothaman, Senior Scientist CIFA, = for his=20 critical appraisal of the manuscript. Thanks are also due to Shri n. k. = Acharya,=20 Technical Officer, and Miss Bithi Mandal, SRF CIFA, for their help in = data=20 analysis and manuscript preparation respectively.


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Received: 17 February = 1998
Accepted:=20 15 January 1999


RATH, S. C., S. D. GUPTA, = S. DASGUPTA:=20 Potaknuto slobodno mrijescenje i dvostruko mrijescenje bijelog amura u=20 mrijestilistu hranjenog smjesom bez prirodne hrane. Vet. arhiv 69, 7-15, = 1999.=20

SAZETAK =

U bijelog amura = (Ctenopharyngodon=20 idella, Val.) moze se upravljanjem nacinom hranidbe i poboljsanim = vodenjem=20 mrijestilista potaknuti slobodno mrijescenje. Kod matica hranjenih = smjesom bez=20 prirodne hrane (sojina i kikiriki pogaca, rizine mekinje i riblje = brasno)=20 izazvano je mrijescenje i usporedeno s mrijescenjem jednakih matica = bijelih=20 amura hranjenih ad libitum vodenim biljem (Hydrilla=20 verticilliata). Uspjeh slobodnog mrijescenja skupine bez biljne = hrane bio je=20 82.2%, a u matica hranjenih vodenim biljem 20.0%. Prosjecna plodnost, = postotak=20 oplodnje i prezivljavanje mlada odnosili su se u matica hranjenih bez = prirodne=20 hrane prema istome u matica hranjenih vodenim biljem kao=20 0.90=B10.15=D7105 prema 0.47=B10.13=D7105, = 89.6=B15.33 prema=20 68.8=B123.1 i 0.76=B10.13=D7105 prema = 0.25=B10.08=D7105. Matice=20 hranjene bez prirodne hrane mogle su se mrijestiti dvaput i davati=20 0.45=B10.11=D7105 kg mlada po kg tjelesne mase s razmakom od = 70 dana=20 izmedu dva uzastopna mrijesta. Potaknuto slobodno mrijescenje bijelog = amura=20 pospjeseno je blagim strujanjem vode (2-3 m u sekundi) i manjom dubinom = vode=20 (0.5-0.6 m) u zajednickom bazenu za mrijescenje.

Kljucne rijeci: = bijeli amur,=20 Ctenopharyngodon idella (Val.), smjesa bez prirodne hrane, prirodna = hrana,=20 Hydrilla verticilliata, slobodno mrijescenje, dvostruko = mrijescenje=20

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