Comparisons of growth performance of African catfish (Clarias gariepinus BURCHELL, 1822) fingerlings fed different inclusion levels of black soldier fly (Hermetia illucens) larvae meal diets

Talamuk, Raphael (2016-03)

Thesis (MSc)--Stellenbosch University, 2016.

Thesis

ENGLISH ABSTRACT: Fish food are a good source of quality protein and other essential nutrients required in human diets. The health benefits of eating fish have been extensively reported. Fish provide the global population with 17% of animal protein intake. However, fish supply from capture fisheries is believed to be stagnant or declining and is not likely to increase in the future. Aquaculture is widely acknowledged as having the potential to fill this gap in food fish production for the human population. One of aquaculture’s drawbacks is heavy reliance on non-sustainable protein sources for aqua feed. The search for alternative and sustainable protein sources has rendered insects as an attractive option in fish diets, since fish naturally consume insects. Insects have a satisfactory amino acid profile and are rich in fats, minerals and vitamins. This study investigated the effects of different inclusion levels of black soldier fly (BSF) larvae meal in the diet of African catfish (Clarias gariepinus) fingerlings. The production parameters and feed utilisation of fish that received the control diet and the BSF supplemented diets were compared. Moreover, the influence of these different diets on water quality parameters, gut histology and body composition of the experimental fish were investigated. Four experimental diets were formulated containing 0% (control), 10%, 20% or 30% BSF larvae meal. A total of 720 fingerlings (5 – 6 g) were randomly allocated to four treatments with six replicates per treatment. The trial was terminated after a 91 day feeding period. Proximate analyses were performed on the experimental diets on a dry matter basis. Although the experimental diets were prepared to be similar iso-nitrogenous and iso-caloric, the proximate analysis showed crude protein content ranged from 41.50% - 44.24%, and crude fat ranged from 11.16% - 16.49%. The gross energy ranged from 19.10 – 20.06 MJ/kg. For statistical analysis, the level of significance used was at p-value 0.05. Treatment effects with p-values less than 0.05 were considered significant. Alternatively, treatment effects with p-values more than 0.05 were not significantly different. If the ANOVA test was found less than 0.05, then Bonferroni post hoc test for least square means was used for multiple comparisons. The results showed that water quality parameters fluctuated within the acceptable range for African catfish and did not compromise the growth of fish between treatments. The growth of fish that received the control diet and 10% BSF diet were not significantly different (P >0.05); however, both were significantly different (P < 0.05) from fish that received BSF 30% larvae meal diet. The fish fed BSF 10% and BSF 20% larvae meal diets were not significantly different from each other. No significant difference in feed utilisation between treatments in terms of average daily gain, feed conversion ratio, protein efficiency ratio and specific growth rate were observed. No differences (P > 0.05) were found in dressing percentages between treatments. The proximate composition of the catfish showed no difference (P > 0.05) in percentage moisture, protein, lipids and ash between treatments. This study shows that BSF larvae meal did not affect the proximate body composition of the African catfish at any tested inclusion levels compared to the control diet. Gut histology of fish that fed on the control diet, 10% BSF, 20% BSF and 30% BSF were compared. No significant differences were found in height of mucosal folds and mucosal folds area between treatments. Significant differences were found in thickness of muscular layer between treatments. The results suggest that BSF larvae meal did not negatively affect intestine morphology in African catfish fingerlings, at least for the 91 day feeding period. This study showed that BSF larvae meal is a viable protein source in the diet of African catfish. Furthermore, this investigation suggests that if unprocessed BSF larvae meal should be used for catfish production, the inclusion level should not exceed 10%. Moreover, this study recommends the defatting of BSF larvae to enable high inclusion levels in the diet of African catfish.

AFRIKAANSE OPSOMMING: Vis as voedsel is ‘n goeie bron van kwaliteit proteïene en ander essensiële voedingstowwe benodig in menslike diëte. Die gesondheidsvoordele van vis eet word wyd verkondig. Vis voorsien die wêreld populasie met 17% van hul dierlike proteïen inname. Nieteenstaande, visvoorsiening vanaf vangste word beskou as stagnant of afnemend en word gesien dat dit nie sal toeneem in die toekoms nie. Akwakultuur word wyd beaam dat dit die potensiaal het om die gaping te vul in aanvraag vir vis vir die mensdom. Een van die vernaamste struikelblokke is die afhanklikheid van akwakultuur op nie-volhoubare proteïenbronne vir akwavoere. Die soektog na alternatiewe en volhoubare proteïenbronne het insekte as ‘n aantreklike opsie vir visdiëte geplaas, want vis vreet natuurlik insekte. Insekte het ‘n aanvaarbare aminosuurprofiel en is ryk in vette, minerale en vitamiene. Hierdie studie het die effek van verskillende insluitingsvlakke van venstervlieg (VV) Hermetia illucens larwe-meel in die diet van die Afrika baber (Clarias gariepinus) vingerlinge ondersoek. Die produksie-parameters en voerverbruik van die vis wat die kontrole-diët en die VVM-supplement diëte ontvang het, vergelyk. Verder, is die invloed van die verskillende diëte op waterkwaliteitsparameters, dermhistologie en liggaamskomposisie van die eksperimentele vis ondersoek. Vier eksperimentele diëte is geformuleer, bevattende 0% (kontrole), 10%, 20% of 30% VV larwe-meel. ‘n Totaal van 720 vingerlinge (5-6 g) was ewekansig geallokeer vir vier behandelings met ses herhalings per behandeling. Die proef is gestaak na ‘n 91 dae voedingsperiode. Proksimale analises is uitgevoer op die eksperimentele diëte op ‘n droë materiaal basis. Alhoewel die eksperimentele diëte voorberei is om dieselfde iso-stikstofagtig en iso-kalories te wees, het die proksimale analise aangedui dat die ruproteïen-inhoud gewissel het van 41.50% - 44.24% en ruvette van 11.16% - 16.49%. Die bruto-energie het gewissel van 19.10 – 20.06MJ/kg. Vir die statistiese analises is die beduidenheidsvlak van p-waarde 0.05 gebruik. Behandelingseffekte met p-waardes kleiner as 0.05 is as beduidend aanvaar. Alternatiewelik, is behandelingseffekte met p-waardes groter as 0.05 as nie-beduidend aanvaar. Indien die ANOVA-toets minder as 0.05 was, is die Bonferroni post hoc toets gebruik vir die kleinstekwadrate gemiddels vir meertallige vergelykings. Die resultate het getoon dat die waterkwaliteitsparameters gewissel het binne die aanvaarbare gebied vir Afrika babers en dit het nie die groei van die vis belemmer tussen die behandelings nie. Die groei van die vis wat die kontrole-diët en 10% VV meel ontvang het, het nie beduidend verskil nie (P>0.05); alhoewel, beide het beduidend verskil (P < 0.05) vir die vis wat VV 30% larwe-meel diët ontvang het. Die vis gevoer met VV 10% en VV 20% larwe-meel het nie beduidend van mekaar verskil nie. Geen beduidende verskille is waargeneem in voerinname tussen die behandelings in terme van gemiddelde daaglikse toevoeging, voeromsettingsverhouding, proteïeneffektiwiteitsverhouding en spesifieke groeitempo nie. Geen verskille (P > 0.05) is waargeneem in die uitslagpersentasie tussen behandelings nie. Die proksimale samestelling vir die babers het geen beduidende verskille getoon nie (P > 0.05) vir persentasie vog, proteïene, vette en as tussen die behandelings. Die studie dui daarop dat die VV larwe-meel nie die proksimale liggaamskomposisie van die Afrika baber beïnvloed het nie by enige van die verskillende insluitingsvlakke in vergelyking met die kontrole-diët. Dermhistologie van die vis gevoer met die kontrole-diët, 10% VV, 20%VV en 30% VV is vergelyk. Geen beduidende verskille is waargeneem in terme van die hoogte en area van die mukosale voue tussen die behandelings nie. Beduidende verskille is wel waargeneem in die dikte van die spierlaag tussen die behandelings. Die resultate toon dat VV larwe-meel geen negatiewe effek op die intestine morfologie van die Afrika baber vingerlinge gehad het nie; ten minste vir die 91 dae voedingsperiode. Die studie het aangedui dat VV larwe-meel ‘n haalbare proteïenbron in die dieët van die Afrika baber kan wees. Verder, toon die ondersoek dat indien die ongeprosesseerde VV larwe-meel vir die produksie van babers gebruik word, die insluitingsvlakke nie meer as 10% moet wees nie. Die studie stel voor dat die ontvetting van VV larwe moet plaasvind om hoër insluitingsvlakke in die dieët van Afrika babers te bewerkstellig.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/98471
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