Thesis (MPhil)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: 60-day growth experiment was conducted to investigate the effect of dietary Lcarnitine
supplementation on the production performance parameters of Mozambique
tilapia, Oreochromis mosambicus. A number of approximately 140 tilapia fry with
average weight of l.4g ± 0.71g were stocked in each of 40 fine-meshed hapas
(I mx 1mx 1.5m) submerged within a complete recirculation pond system. During the first
30 days of the experiment water temperatures ranged from 19 to 23°C where after it
decreased to 16-20°C for the consecutive 30-day period. Dietary treatments consisted of 8
replicates of 5 levels of L-carnitine supplementation labelled as Co, C250,C500, C750 and
C 1000represented Omg, 250mg, 500mg, 750mg and 1000mg L-carnitine supplementation
per kg feed respectively. Results were analyzed for significant differences using one-way
analysis of variance (ANOVA) and Tukey's pairwise comparison test for growth rate,
feed intake (FI) and feed conversion efficiency. After completion of the trial 8 fish from
each hapa were sacrificed and analyzed for cephalosomatic index (CSI), dress out
percentage (viscera, gills and head excluded), viscerosomatic index (VSI) and
hepatosomatic index (HSl).
Poor production performance results were generally observed as water temperatures were
sub-optimal, especially during the second 30-days period. Results from the trial indicate
no significant differences (P>0.05) between treatments for weight gain, FCR, FI and VS!.
A negative trend was observed for FCR with increasing level of L-carnitine
supplementation for both the first 30-day period (1.50±0.07, 1.53±0.08, 1.58±0.09 and
1.61±0.17 for C250,C50Q,C750and C 1000)as well as for the consecutive lower temperature
30-day period (2.22±0.10, 2.25±0.ll, 2.27±0.28 and 2.29±0.2l for C250, C500, C750 and
C 10(0)'Although statistically not significant, fish fed the C250showed better performance
in dress out percentage weight either than the control or the higher levels. The increasing
trend for head weight with increasing level of L-carnitine supplementation were
significant (P<0.05) from Co and C250with and above C500.The decreasing trend for liver
weight with increasing level of L-carnitine supplementation became significant (P<0.05)
with and above C750.The results of the current study showed a trend in the improvement
of L-carnitine on the production performance parameters. However, the natural content of
L-carnitine in the basal diet impaired with the inclusion levels, thus further research at
lower inclusion levels is recommended. / AFRIKAANSE OPSOMMING: 'n Proef oor 'n tydperk van 60-dae is onderneem om die effek van L-karniten aanvulling
op produksie prestasie parameters van Mosambiek tilapia (0. mosambicusi te ondersoek.
140 tilapia vingerlinge met 'n gemiddelde massa van lAg ± 0.7lg is ewekansig
uitgeplaas in 40 eksperimentele hapa-hokkies (lmxlmx1.5m) in "n hersirkulasie
sementdam-stelsel. Gedurende die eerste 30 dae van die proef het water temperatuur
gewissel tussen 19 to 23°C waarna dit gedaal het na tussen l6-20°C vir die opeenvolgende
30-dag periode. Proef-rantsoen behandelings het bestaan uit 8 herhalings van 5 vlakke
van L-karnitien aanvulling, naamlik Co,C250, C500, C750 en CIOOOvir Omg, 250mg, 500mg,
750mg en 1000mg L-karnitien aanvulling per kg voer afsonderlik. Resultate was ontleed
vir betekenisvolle verskille deur gebruik te maak van analise van variansie (ANOVA)
ontleding en die Tukey se vergelykende toets vir groeitempo, voerinname en
voeromsettingsverhouding. Aan die einde van die proefperiode is 8 visse van elke hapa
ontleed vir liggaamskomponent-samestelling (kop-, ingewande- en hepatosomatiese
indekse.
Ondergemiddelde produksie resultate is waargeneem wat toegeskryf kan word aan
onder-optimale water temperature, veral gedurende die tweede 30-dag periode van die
proef. Proef resultate het geen betekenisvolle verskille (P>0.05) in massatoename,
voeromsettingsverhouding (VOV) of visserosomatiese indeks tussen behandelings
getoon nie. 'n Negatiewe neiging is waargeneem vir VOV met toenemende vlakke
van L-kamitien insluiting vir beide die eerste 30 dag periode (1.50±0.07, 1.53±0.08,
1.58±0.09 and 1.61±0.17 for C250, C500, C750 and CIOOO) sowel as vir die opvolgende
30-day periode nie (2.22±0.10, 2.25±0.11, 2.27±0.28 and 2.29±0.21 for C250, C50o,
C750 and CIOOO). 'n Toenemende neiging vir kop-massa met toenemende L-kamitien
insluiting was betekenisvol (P<0.05) vanaf Co en C250 met en hoër as C500. 'n Dalende
neiging vir lewermassa met toenemde L-kinsluiting was betekenisvol (P<0.05) met en
hoër as C750. Resultate van die proef dui oor die algemeen op 'n neiging tot verbeterde
produksie prestasie parameters van tilapia vingerlinge met toenemde insluiting van Lkamitien.
Verdere navorsing word aanbeveel om die invloed van natuurlike Lkamitien
in die proteïen-bronne van die basaalrantsoen te op die gebrek aan
betekenisvolheid van hierdie neiging te verklaar.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/50142 |
| Date | 12 1900 |
| Creators | Tekle, Esayas Welday |
| Contributors | De Wet, Lourens, Brink, Danie, Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 46 p. : ill. |
| Rights | Stellenbosch University |
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