Lilian Dena dos Santos

Redução da proteína da dieta com base no conceito de proteína ideal para tilápias-do-nilo (Oreochromis niloticus) criadas em tanques-rede

This study was carried out to evaluate the performance of Nile tilapia, cultured in net pens, and fed diets containing 27.0 (control), 25.2, 24.3, and 22.7% of digestible protein. Crystalline amino acids (L-lysine, DL-methionine and L-threonine) were added to keep amino acid levels according to the ideal protein profile and to simulate amino acid levels of the control diet. Fish (34.63±1.19 g) were hand-fed one of the four isoenergetic (3,075 kcal of digestible energy/kg, as fed basis) experimental diets until apparent satiation, three times a day during 90 days. A completely randomized design with four treatments, three replicates and 25 fishes per experimental unit was utilized. No effects of dietary digestible protein levels on weight gain, feed conversion, protein efficiency ratio, empty carcass weight, carcass yield, fillet weight and yield, survival, and hematocrit were observed. It was observed quadratic effect on feed intake and nitrogen excretion, wich increased up to 24.41 and 24.92% of dietary digestible protein, respectively. The reduction of digestible protein levels resulted in a linear increase of nitrogen retention. It was concluded that it is possible to reduce the dietary digestible protein from 27.0 (29.1% of CP) to 24.3% (26.6% of CP) in amino acid supplemented diets (based on ideal protein concept), for juvenile Nile tilapia, cultured in net pens, without adverse effects on growth performance, carcass yield and composition, hematological parameters and cost of diet/kg of fillet gain.

Exigência de fósforo disponível para juvenis de tilápia-do-nilo

Available phosphorus requirement of juvenile Nile tilapia (Oreochromis niloticus) was determined. A total of 352 fishes with initial weight of 0.41 g ± 0.30 g was assigned to a completely block experimental design were used, with four levels of available phosphorus and four replications. Diets with 32.0% CP and 3,050 kcal DE/kg were supplemented with dicalcium phosphate to obtain levels of 0.21; 0.40; 0.56 and 0.71% of available phosphorus in the diets. Diets were handly fed during 120 days. No effects of available phosphorus levels on feed intake, content of protein and ether extract in the carcass and mortality rate were observed. The available phosphorus levels showed a quadratic effect on weight gain, feed:gain ratio, protein efficiency ratio and the calcium percentage in the bones, that were better in levels 0.55, 0.52, 0.52, and 0.60% of available phosphorus, respectively. Data analysis by broken-line regression method indicated adequate deposition of phosphorus in the bone with 0.64% of phosphorus in the diet. The requirement of available phosphorus for juvenile Nile tilapia raised in recirculation tanks is of 0.52%.

Exigência de fósforo disponível para tilápia-do-nilo (35 a 100 g)

The objective of this work was to determine the available phosphorus requirement of Nile tilapia. A total of 144 fishes with initial weight 35.33 ± 0,66g LW were distributed to a completely randomized blocks design, with four treatments and three replicates. Diets with 29.0% CP and 2980 kcal/kg DE and four available phosphorus levels (0.25; 0.35; 0.45 e 0.55%) were used. The dicalcium phosphate was used as phosphorus source. The diets were fed to the fishes three times a day to apparent satiation, during 46 days. No significant effect of dietary available phosphorus on hepatosomatic index, survival rate and carcass water and protein contents were observed. The increase of available phosphorus levels in the diet promoted linear increase of average weight gain and phosphorus excretion, and content of ash in carcass and ashes, calcium. There was a quadratic effect of dietary available phosphorus on feed intake, feed conversion ratio and protein efficiency ratio and the best values were obtained with 0.37, 0.48 and 0.48%, respectively. Dietary requirement of available phosphorus for Nile tilapia from 35 to 100 g is 0.48% (0.53% DM).

Farelo de soja na alimentação de tilápias-do-nilo durante o período de reversão sexual

Eight hundred Nile tilapia larvae with two days old were used to evaluate the inclusion of soybean meal in diets fed Nile tilapia during the sex reversion period (30 days). The experiment was analyzed as a completely randomized blocks, with four treatments and four replications. A net tank with 50 larvae was considered an experimental unit. The treatments were formulated to be isoprotein and isonitrogenous (38.6% of digestible protein and 3,800 kcal/kg of digestible energy), with increasing levels of soybean meal inclusion 0, 16, 34 and 42%. Average final weight and length linearly increased as the dietary soybean meal levels increased. No treatment effect on survival and body condition was observed. It is recommend to include up to 42% of soybean meal in Nile tilapia diets in the sexual reversion phase.

Desempenho e morfometria intestinal de juvenis de tilápia-do-nilo alimentados com dietas suplementadas com L-glutamina e L-glutamato

This work was carried out to evaluate levels of L-glutamine and L-glutamate in diets for Nile tilapia juveniles (0.60 ± 0.1 g). A complete randomized experimental design with four diets and three replicates and 90 fish per experimental unit was used. It was used a control diet with 29% of digestible protein and 2,940 kcal/kg of digestible energy supplemented with L-glutamine and L-glutamate at the proportion of 0, 1, 2 and 3% of diet, during 85 days. It was not observed effect of dietary L-glutamine and L-glutamate on feed intake, food conversion, protein efficiency rate, nitrogen retention efficiency, hepatic somatic index, chemical body composition, blood ammonia and urea. It was observed a linear increase on gain weight and a quadratic effet on villus height when levels of L-glutamine and L-glutamate increased. The addition of L-glutamine and L-glutamate increases the weight gain and intestinal villus height of Nile tilapia.

Ácido linoléico conjugado (CLA) em dietas para tilápia-do-nilo: desempenho produtivo, composição química e perfil de ácidos graxos

The objective of this work was to evaluate the influence of the addition of CLA in the diet on Nile tilapia productive performance, chemical and fatty acids composition. Eighty reversed fish with 109 ± 10 g were used, distributed in eight tanks (0.8 m3 each) in density of ten fishes/tank, during 90 days. It was evaluated the inclusion in the diets of 2% of CLA (Luta-CLA®-BASF, Brazil) with 60% of isomers (cis-9,trans-11 and trans-10,cis-12) and 40% of vehicle (oleic acid and other fatty acids). As diets, a commercial extruded ration with 29% CP and 3000 kcal DE/kg of ration was used. At the end of the experiment all fishes were used for the evaluation of performance, of chemical composition and profile of fatty acids on liver and fillets. No differences for protein efficiency ratio, carcass yield, hepatosomatic index and visceral fat, were observed with the addition of CLA in the diet. The addition of CLA in the diet improved weight gain, feed intake and feed conversion ratio. Fishes fed diets with addition of CLA showed an increase in saturated fatty acids composition, reduction in n-6 fatty acids in the fillets and increase in n-3 fatty acids and total polyunsaturated fatty acids composition in the liver. There was an increase of protein in fillets of tilapia fed with rations enriched with CLA. CLA utilization improve productive performance, affect the fatty acids metabolism and pattern in fillets and liver and increase the body protein of Nile tilapia.

Avaliação sensorial e rendimento de filés defumados de tilápia (Oreochromis niloticus Linnaeus, 1757) na presença de alecrim (Rosmarinus officinalis)

Objetivou-se com este trabalho avaliar o efeito das formas de processamento e do alecrim na defumacao dos troncos e files sem pele de tilapia do Nilo sobre o rendimento e as caracteristicas organolepticas. Independente da forma de processamento aplicada, os files defumados na presenca do alecrim apresentaram menor rendimento. Foi tambem observado que os files obtidos a partir dos troncos defumados proporcionaram maiores rendimentos. Analisando a forma de processamento dos files defumados, os provadores apresentaram maior aceitacao para files (FIL) (2,88) em relacao aos files a partir dos troncos defumados (FTD) (2,63). A presenca de alecrim nos files, independente da forma de obtencao do produto final, nao foi significativo para aparencia, cor, aroma e aceitacao geral, em que as notas transformadas variaram de 2,70 a 2,77. Em relacao as analises organolepticas das porcoes do defumado, a preferencia foi maior para o consumo dos FIL em relacao aos FTD. Os provadores nao notaram diferencas quanto ao acrescimo de alecrim aos FIL e FTD, exceto para teor de sal.

Níveis de teonina em rações para tilápias-do-nilo

This experiment was conducted to determine the dietary threonine requirements for Nile tilapia. The fishes (37.61 ± 1.16 of initial weight) were allotted to a completely randomized design with four treatments, three replicates and 25 fishes per experimental unit. It was used a reference diet with 27% of CP and 3,000 kcal of DE/kg, supplemented with L-threonine, resulting in diets with 0.92, 1.06, 1.21, and 1.35% of total threonine. Synthetic amino acids were added to mantain their profile according to the ideal protein concept. Fishes were fed ad libitum during 110 days. No effects of dietary threonine levels on feed intake, liver weight, hepatic somatic index, carcass yield, fillet yield and fillet water composition (CP and EE) were observed. It was observed linear increase on weight gain, feed:gain ratio, protein efficiency rate, nitrogen retention, carcass weight, fillet weight and ash content in fillet. Considering data of performance, cost/kg of weight gain and cost/kg of fillet weight, the dietary total threonine requirement is of 1.35% [5.51% of digestible protein or 74% of lysine (based on the ideal protein concept)] for Nile tilapia from 38 to 351 g, reared in net pens.

Exigência de Proteína Digestível para Juvenis de Tilápia do Nilo (Oreochromis niloticus) em Baixa Temperatura

Este trabalho objetivou determinar a exigencia de proteina digestivel (PD) para juvenis de tilapia do Nilo. Foram utilizados 125 animais (9,9 0,3 g) distribuidos, em 25 caixas de 250 L, num delineamento completamente casualizado com cinco tratamentos e cinco repeticoes. A temperatura media da agua foi de 21,2 e 22,9oC, respectivamente para a manha e tarde. Os tratamentos foram constituidos de cinco racoes isoenergeticas, isocalcicas e isofosforicas com diferentes niveis de PD (20, 25, 30, 35 e 40%). A PD influenciou o peso final medio e a percentagem de ganho de peso (P<0,01), a conversao alimentar, a proteina e gordura corporal, consumo de proteina digestivel, taxa de eficiencia proteica e retencao de proteina digestivel (P<0,05). O melhor teor de PD para racoes para tilapia do Nilo de 10 a 30 g, em baixas temperaturas, foi de 25%, entretanto, a sua variacao ate 30% proporcionarem resultados de desempenho, carcaca e utilizacao da proteina da racao, semelhantes.

Conjugated linoleic acid in pacu diets: deposition time, performance and fatty acids profile

Avaliou-se a influencia da adicao (1,2%) de acido linoleico conjugado (CLA) na dieta sobre o desempenho, a deposicao e o perfil de acidos graxos na carne de pacus. Foram utilizados 112 pacus em crescimento (256,19 ± 24,09), distribuidos em delineamento inteiramente casualizado, com dois tratamentos e quatro repeticoes, em oito tanques (1 m3 cada), e alimentados ate a saciedade aparente, tres vezes ao dia, durante 60 dias. Utilizou-se dieta extrusada, com 28% PB e 3.000 kcal ED/kg de racao. A cada duas semanas, foram coletados oito peixes de cada tratamento (dois de cada repeticao) para determinar a composicao de acidos graxos no tempo. Pela analise de Broken-line, a maxima deposicao do cis-9, trans-11, trans-10, cis-12 e do CLA total foi estabelecida com 23, 20 e 21 dias, respectivamente. Nao foram observadas diferencas no desempenho e na composicao quimica do peixe inteiro, do file e do figado. A deposicao de CLA ocorreu em altas concentracoes em todos os tecidos do pacu. O fornecimento de CLA na dieta afetou a composicao de acidos graxos poliinsaturados e monoinsaturados no peixe inteiro, file e figado. A deposicao de CLA em pacus corresponde a ate 3,6% dos lipidios totais no peixe inteiro e no file.