In vitro assays predicts mineral retention and apparent protein digestibility of different fish feed measured using a juvenileP. mesopotamicusmodel

Abstract

Feed chemical composition only provides information about nutrient content of a diet, but not its bioavailability. The aims were to determine mineral bioaccessibility and protein digestibility of three different fish feed, using in vitro methods and to correlate them with feed mineral retention and apparent protein digestibility measured by juvenile Piaractus mesopotamicus model, considering elliptical joint confidence region (EJCR) of weighted least-squares analysis. For in vivo assays, juvenile P. mesopotamicus were randomly stocked into conical tanks and fed during 38 days with a commercial diet, an experimental diet, or the same experimental diet added with phytase (0.2 g/kg). Total body mineral retention (mineral bioavailability indicator) and apparent protein digestibility of different diets were measured. For in vitro methods, mineral dialysability (mineral bioaccessibility indicator) and protein digestibility of the same diets were determined. No significant difference in morphometric and haematological markers were detected between diets. For iron, zinc and phosphorous bioavailability, and protein digestibility, weighted least-squares analysis showed the optimal point (1, 0) was included in EJCR, indicating in vivo and in vitro methods were comparable and correlated satisfactorily. In vitro methods were able to reproduce accurately the results obtained from traditional in vivo assays using juvenile P. mesopotamicus model. K E Y W O R D Sfish feed, mineral dialysability, mineral retention, protein digestibility

Role of microbial phytases in improving fish health

“…Vitamin D₃ (cholecalciferol) and its compounds might be involved in improving phytase response in fish. It increases Ca absorption and restricts it from making phytate‐Ca complex which indirectly stimulates the breakdown of phytate and enhances the utilization of hydrolyzed P 28,29,82 . As reported in O .…”

“…171 Vitamin D₃ (cholecalciferol) and its compounds might be involved in improving phytase response in fish. It increases Ca absorption and restricts it from making phytate-Ca complex which indirectly stimulates the breakdown of phytate and enhances the utilization of hydrolyzed P. 28,29,82 As reported in O. mykiss, providing low level of vitamin D₃ with phytase in soy protein concentrate feed enhances WG. 28,29 Opposite to this, there is no effect of supplementing vitamin D₃ on P. fulvidraco along with phytase.…”

In-vitro digestion models: a critical review for human and fish and a protocol for in-vitro digestion in fish

“…Because protein is the most expensive and difficult ingredient to be replaced, research on developing fish meal replacement, using the in-vitro method, primarily targeted for carnivorous fish. Several other fish species have also been studied based on their local economic importance [7,16,[83][84][85].…”

“… 37 15 11 protein ingredients DH, FAA APD Centropomus undecimalis Two stage pH stat [ 87 ] 8 - 25 60 10 protein ingredients DH, invivo Acipenser baeri One step intestine stage, [ 168 ] 3.4&7.8 256 & 1460 28 90 acid Poultry by product on several different grade Pepsin assay FAA APD Lates calcarifer Two stage membrane reactor, with commercial pepsin and fish crude intestinal extract [ 169 ] 9 2.5 25 90 4 microalgae SDS page, FAA Senegalese sole One stage intestinal digestion [ 170 ] 2 & 7 nd 37 120 & 120 Three commercial diet In vivo assessment Residual protein Minerals (P, Fe, Zn) P.mesopotamicus Two step digestion with final product dialysis separation. Added bile extract [ 16 ] 3.5 & 8 - - 15&45 16 protein ingredients DH, FAA Amphilophus trimaculatus Intestinal extract …”

“…The nutrient digestibility assessment is typically conducted in-vivo by feeding trials on the fish species of interest, measuring the growth rate, fecal content, and fish survival rate [ 15 ]. Even though it provides a more accurate and representative result, the in-vivo method is lengthy and expensive [ 16 ]. The alternative is the in-vitro method, conducted by simulating the physiology of fish gastrointestinal tract using laboratory equipment.…”