Characterization of digestive enzymes protease and alpha-amylase activities in the thick-lipped grey mullet (Chelon labrosus , Risso 1827)

Abstract

Activities of pepsin, trypsin, chymotrypsin, alphaamylase and lipase, as well as their optima and stability to pH and temperature, were determined in digestive extracts of thick-lipped grey mullet, Chelon labrosus, of three different sizes: Group 1 (45.2 AE 3.0 g), Group 2 (180.9 AE 4.2 g), and Group 3 (328.5 AE 43.3 g). SDS-PAGE zymograms were also used to assess the role of serine proteases in the digestive tract of C. labrosus. On the other hand, possible changes in the digestive enzyme profile of C. labrosus during development were observed, with a comparatively lower pepsin activity, higher activities of alkaline proteases and alpha-amylase and no lipase activity recorded in pre-adult specimens. It is suggested that these variations are linked to the changes in diet composition with age, moving from a partly carnivorous to a more herbivorous feeding habit.

Digestive enzymes and gut morphometric parameters of threespine stickleback (Gasterosteus aculeatus): Influence of body size and temperature

“…Digestion is an elementary process in fish metabolism because it determines the availability of nutrients needed for all biological concerns [ 2 ]. Digestive enzymes are one of the cornerstones of digestion for the net efficiency of the whole digestive process mainly depends on the type and functional characteristics of these parameters [ 3 ]. Degradation of nutrients in the digestive tract of fish largely depends on available enzymes.…”

“…It is influenced by biotic (size, age, origin), and abiotic (temperature, season, food) parameters [ 7 ], which can alter enzyme profiles or activity levels. Based on their food preferences, fish are conventionally classified as carnivorous, herbivorous or omnivorous [ 3 ]. They can also be classified according to their gut morphometric parameters, i .…”

AKTIVITAS PROTEASE DAN AMILASE PADA IKAN SIDAT <em>Anguilla bicolor</em> McClelland)

“…Jadi aktivitas protease cenderung menurun seiring dengan pertambahan berat tubuh dan umur ikan. Perubahan tersebut diakibatkan oleh perbedaan ontogenik ikan serta perubahan kebiasaan makan atau interaksi dari keduanya (Pujante et al, 2016).…”

“…Barbus sharpeyi yang merupakan ikan herbivora memiliki aktivitas amilase yang lebih tinggi daripada Cyprinus carpio (omnivora), maupun Aspius vorax (karnivora). Perubahan katagori pakan dari omnivore menjadi herbivore yang menghasilkan peningkatan aktivitas amilase juga telah ditunjukkan pada ikan Chelon labrosus (Pujante et al, 2016). Jadi tampaknya ikan sidat, yang termasuk ikan karnivora memiliki kebutuhan karbohidrat yang rendah, sehingga memiliki aktivitas amilase yang rendah dan tidak mengalami perubahan aktivitas dengan perubahan ukuran ikan.…”

“…Lundstedt et al (2004) menyatakan bahwa selain kadar pakan, faktor yang dapat mempengaruhi aktivitas amilase ikan yaitu kemampuan usus, kebiasaan makan, kompleksitas struktur pakan, suhu dan musim. Aktivitas amilase dalam usus dipengaruhi oleh kelenjar pencernaan (hepatopankreas), pH, temperatur, jumlah protease aktif di dalam usus, konsentrasi enzim dengan substrat dan kebiasaan makan ikan (Caruso et al, 2008;Murashita et al, 2013;Pujante et al, 2016). Lebih lanjut, Novita et al (2006) menyatakan bahwa perubahan pH dan temperatur akan berpengaruh terhadap perubahan muatan dan struktur pada enzim maupun substrat yang selanjutnya dapat memberikan dampak pada stabilitas reaksi enzimatis.…”