Bol. Inst. Pesca, São Paulo, 44(vol. esp.): 35 - 46, 2017
Doi: 10.20950/1678-2305.2017.35.46
CRUDE PROTEIN IN DIETS FOR NILE TILAPIA BROODFISH*
Manoel Joaquim Peres RIBEIRO
1
; Mariana Machado EVANGELISTA
1
; Eduardo Antônio
SANCHES
2
,1
; Giovani Sampaio GONÇALVES
3
; Elizabeth ROMAGOSA
4
,1
ABSTRACT
The effect of different levels of crude protein (32A, 32B, 36, 38, 44 and 50% CP; 3,500 kcal digestible
energy) on Nile tilapia broodstock was assessed. After 30 experimental weeks (Sept./14 to
Mar./15), 91.0% of eggs from fish fed 44% CP hatched and produced 16.4% more viable larvae than
the treatment with 32% CP. Egg production and absolute fecundity were similar between
treatments (p>0.05). Sperm motility, average path, straight line and curvilinear velocities showed
satisfactory values with 44% CP, unlike 36% CP. Lower profitability was observed with 32% CP;
profit increased as protein level upped. Statistically significant responses were not found for
reproductive performance of females. Results were satisfactory for commercial-scale production as
crude protein increased. The initial hypothesis was demonstrated for most parameters assessed in
males, larvae growth and economic viability. Therefore, it is recommend the use of diets with 44%
CP for Nile tilapia brood fish.
Keywords: larvae; reproductive performance; semen; survival
PROTEINA BRUTA EM DIETAS PARA REPRODUTORES DE TILÁPIA DO NILO
RESUMO
O efeito de diferentes níveis de proteína bruta (32A, 32B, 36, 38, 44 e 50% PB; 3500 kcal energia
digestível) em reprodutores de tilápia do Nilo foi avaliado. Após 30 semanas experimentais (set./14
a mar./15), 91,0% dos ovos de peixes alimentados com 44% PB, eclodiram e produziram 16,4% de
larvas viáveis a mais do que o tratamento que recebeu 32% PB. A produção de ovos e a
fecundidade absoluta foram semelhantes entre os tratamentos (p>0,05). A motilidade e a velocidade
médias do esperma, em linha reta e curvilínea, apresentaram valores satisfatórios no tratamento em
44% CP, ao contrário de 36% PB. Observou-se baixa rentabilidade com 32% PB; todavia, o lucro
aumentou com o nível de proteínas na dieta. Respostas estatisticamente significativas não foram
encontradas para o desempenho reprodutivo de fêmeas. Os resultados foram satisfatórios para a
produção em escala comercial com o aumento da proteína bruta. A hipótese inicial foi demonstrada
para a maioria dos parâmetros avaliados em machos, crescimento de larvas e viabilidade
econômica. Portanto, recomenda-se dieta com 44% PB para reprodutores de tilápia do Nilo.
Palavras-chave: larva; desempenho reprodutivo; sêmen; sobrevivência
Original Article/Artigo Científico: Recebido em 14/12/2016 Aprovado em 06/06/2017
1
Aquaculture Center of UNESP University (CAUNESP). Via de acesso Prof. Paulo Donato Castellani, km 5 CEP: 14.884-
900 Jaboticabal SP Brazil. e-mails: ribeiromjp@gmail.com; mariana.mevangelista@gmail.com
2
UNESP University, Registro Experimental Campus. CEP: 11900-000 Registro SP Brazil. e-mail: eduanches@hotmail.com
3
Fishery Institute, APTA/SAA. Av. Abelardo Menezes, s/n - Zona Rural - Caixa Postal 1052 CEP: 15.025-970 São José
do Rio Preto SP Brazil. e-mail: gsgoncalves@pesca.sp.gov.br
4
Fishery Institute, APTA/SAA. Av. Francisco Matarazzo, 455 Água Branca CEP: 05001-000 SP Brazil. e-mail:
e.romagosa@uol.com.br (corresponding author)
*Financial support: São Paulo Research Foundation FAPESP (process nº 2013/24.474-1)
36 RIBEIRO et al.
Bol. Inst. Pesca, São Paulo, 44(vol. esp.): 35 - 46, 2017
INTRODUCTION
Although in the last few years considerable
progress has been made in the knowledge of the
nutritional demands of Nile tilapia, there is still a
need for further studies on nutrition that consider
different categories of weight or age, as well as
specific studies about broodfish (FURUYA et al.,
2013), especially the supply of essential nutrients
for the development of gonads, eggs and larvae
(LUPATSCH et al., 2010), which is an immediate
need since the aquaculture activity has shown
rapid expansion recently.
In this context, it is important to emphasize
the relevance of providing adequate diets to Nile
tilapia broodfish, a species raised all over the
world and characterized by presenting parceled
asynchronic spawning, with low fecundity rate,
whose reproductive process received special
attention in the last few years (NG and ROMANO,
2013; LUPATSCH et al., 2010; COWARD and
BROMAGE, 2000). Considering the limitations to
gamete quality, and consequently the large scale
production of larvae and fry (NAVARRO et al.,
2014), effects of the addition of crude protein (CP)
to follow the reproductive behavior of this species
were described by GUNASEKERA et al. (1996);
AL-HAFEDH et al. (1999); EL-SAYED and
KAWANNA (2008) and OLIVEIRA et al. (2014).
However, the results of those studies did not
clarify what the adequate demand for protein of
tilapia broodstock is, northe effect of protein on
egg quality (LUPATSCH et al., 2010).
A review published by NG and ROMANO
(2013) on nutrition and feed management of Nile
tilapia explained the need to add high quality
nutrients, mainly during vitellogenesis, in order to
avoid signs of delay in the process of gonad
maturation, low values of hatching, fertilization
and sperm motility rates. Those facts emphasize
the importance of nutrition in reproductive
performance. According to the authors, the levels
of CP that showed the most satisfactory results
were between 30 and 40%, which is such a wide
range. Therefore, makes it difficult to prepare
specific feed. In addition, comparatively to other
nutrients, protein is the most expensive item in
diet formulation for aquatic organisms (NRC,
2011), and that wide range may considerably
interfere with the final cost of production (Âmbar
Amaral Group, Raguife Rações
®
Santa do Sul,
SP/BR; Gonçalves, G.S. 2016, per. comm.). Thus,
the protein level in the feed for broodfish should
be critically analyzed, considering that in practice,
besides egg production and quality, the health
condition of the fish must be assessed when facing
the constant challenges of farming systems, as well
as the economic impact of using different feed.
Due to the need to obtain an adequate diet for
broodfish and knowing how important these
results would be to the activity, the objective of
this experiment was to assess the morphometric,
reproductive and blood parameters of Nile tilapia
broodfish fed diets with different levels of protein,
in addition to economic aspects of larvae produced
by the broodfish studied.
MATERIAL AND METHODS
The experiment was carried out at the Peixe
Vivo Aquacultura
®
fish farm, Santa do Sul-
SP/Brazil (20º12'40"S and 50º55'33"W), from
September/2014 to March/2015, with the
approval of the Animal Ethics Committee, UNESP
University, Jaboticabal Campus/SP/BR (nº
014944/14). Fry of Nile tilapia, GIFT strain - Aqua
América
®
1 were used in this study.
The mean values of water temperature
remained at 28.0 ± 2.23 °C, dissolved oxygen 6.77
± 2.03 mg L
-1
and pH 6.8 ± 0.54, registered with
digital potentiometers. In order to determine
water transparency (m), the Secchi disc was used,
and the values were 32.0 ± 2.67 cm during the
seven months of experiment.
Three thousand eight hundred and forty Nile
tilapia broodfish GIFT strain - Aqua América
®
1
were used: 2,880 females (197.63 ± 62.57 g) and
960 males (218.7 ± 65.05 g). The fish were weighed
(g) and measured (cm) before being placed in
“hapas” (10.0 x 3.0 x 0.80 m, 1.0 mm mesh size), at
a proportion of three females to one male (3F:1M),
a total of 160 fish per hapa, installed in a pond
(2,000 m
2
). In order to obtain better oxygenation in
the hapas and avoid net clogging, a pump system
was installed and pond water was sprinkled onto
the hapas. A completely randomized design was
used, composed by six treatments and four
replications.
Six diets were used in the experiment; four
experimental diets and two commercial diets