Degradation of amino acids by leaching in feeds for shrimp

Abstract

Resumo -As rações para camarão estão entre as mais caras do setor de aquicultura principalmente porque esse tipo de ração deve ter alta estabilidade na água. Este trabalho teve, como objetivo, avaliar a estabilidade de aminoácidos em rações comerciais com diferentes teores proteicos, destinados a camarões na fase larval e juvenil, submetidas à lixiviação. As amostras de ração foram expostas ao processo lixiviatório durante período de tempo de 04, 08 e 12 horas. As análises de degradação de aminoácidos foram realizadas utilizando-se um sistema de HPLC, em modo de gradiente de eluição. Destacadamente, em todas as rações avaliadas, observou-se que a lisina e histidina, foram os aminoácidos essenciais que sofreram menor processo degradativo. É importante ressaltar que a arginina é considerado um aminoácido importante para o crescimento de camarões, e, em ambas as rações com 35% de proteína -RA35 e RB35 -, as perdas deste aminoácido foram de 79% e 89% respectivamente. Os resultados obtidos nesta pesquisa indicam que o processo de lixiviação diminui consideravelmente o conteúdo de aminoácidos das rações. No processo de lixiviação a estrutura física da ração não impede o processo degradação dos aminoácidos. palavras-chave: Litopenaeus vannamei, QuaLidade nutricionaL, estabiLidade.abstract -The feed for shrimp are one of the most expensive in the aquaculture sector, mainly because this type of feed should have high stability in water. This study aimed to evaluate the stability of amino acids in commercial feeds with different protein contents intended for larval and juvenile shrimp subjected to leaching. The feed samples were exposed to the leaching process during the time period of 04, 08 and 12 hours. The analyses of degradation of amino acids were performed using an elution gradient in HPLC system. In all diets evaluated it was found that lysine and histidine are essential amino acids which suffered less degradation processes. It's important to mention that arginine is considered an important amino acid for growth of shrimp. In both feeds with 35% protein (RA35 and RB35) the losses of arginine were 79 and 89% respectively. The results obtained in this study indicate that the leaching process significantly reduced the content of amino acids in the feeds. The physical structure of the feed doesn't prevent the degradation process of amino acids in the leaching process. Key WorDs: Litopenaeus vannamei, nutritionaL QuaLity, stabiLity. ISSN 1981ISSN -1268 PRADO ET AL. (2016) Gaia Scientia (2016). Volume 10(4): 361-371. DegraDação De aminoáciDos por lixiviação em rações para camarãoResumen -Las raciones para el cultivo de camarón se encuentran entre los más caros en el sector de la acuicultura, principalmente porque debe tener una alta estabilidad en el agua. Este trabajo tuvo como objetivo evaluar la estabilidad de los aminoácidos en las dietas comerciales con diferentes niveles de proteína, para los camarones en la etapa de larvas y juveniles, sometidos a lixiviación. Las muestras de alimento fueron expuestos al proceso ...

Effects of Feed Processing Type, Protein Source, and Environmental Salinity onLitopenaeus vannameiFeeding Behaviour

“…Fishmeal is known for its balanced amino acids, contributing to better growth (Wouters et al, 2001; Glencross et al, 2002; Gonzalez-Galaviz et al, 2020). However, the plant-based diets in this study showed higher rates of amino acid leaching (Prado et al, 2016), possibly affecting shrimp feed efficacy.…”

“…Fishmeal’s high- quality protein with balanced essential amino acids contributes to better growth and feed utilization in aquatic animals (Hua et al, 2019; Malcorps et al, 2019). Supplemented amino acids have also been studied for their ability to leach into the water, which can be a problem in shrimp feed due to their slow feeding behaviour (Prado et al, 2016). Despite being supplemented into the soya and pea–based diets, the levels of lysine, threonine and methionine were lower in Diets D1 (SE) and especially D2 (SS).…”

“…Despite being supplemented into the soya and pea–based diets, the levels of lysine, threonine and methionine were lower in Diets D1 (SE) and especially D2 (SS). Previous studies have shown that synthetic amino acids had higher leaching rates (Zarate and Lovell, 1997) with a study stating that 15% of this synthetic lysine was lost within 15 seconds of being immersed (Prado et al, 2016) and levels of free crystalline amino acids in feeds could be reduced by 80% within minutes of being exposed to water (Lopez-Alvarado et al, 1994). The amino acid profiles, particularly the lower levels of lysine, threonine, and methionine in plant-based diets, despite being supplemented, have implications for shrimp growth and survival.…”

“…Shrimp's specialized mouthparts, adapted for different functions during feeding (Nguyen et al, 2018), respond differently to the texture of the feed, influenced by feed processing type and protein source. The texture of the feed, along with nutrient leaching and chemosensory responses, creates intricate interactions affecting shrimp feeding preferences and rates (Prado et al, 2016). Understanding these dietary factors' impact on both the physical and chemical aspects of feed is crucial for optimizing feeding strategies in aquaculture.…”