Estimation of protein digestibility—II. In vitro assay of protein in salmonid feeds

doi:10.1016/0300-9629(94)90107-4

Comparative Biochemistry and Physiology Part A: Physiology

Volume 108, Issues 2–3, June–July 1994, Pages 363-370

https://doi.org/10.1016/0300-9629(94)90107-4 Get rights and content

Abstract

The in vitro digestibility of protein in various salmonid feeds was determined by pH-stat using enzyme fractions from trout pyloric ceca. Data were compared with in vivo digestibility and growth of fish by linear regression analysis. Results indicated that there were good agreements between the degree of hydrolysis of most feed samples and growth of fish. The pH-stat method is not suited for feed samples that have been partially hydrolyzed during their preparation.

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Nutritional and techno-functional properties of Australian Acacia seed flour: Effects of roasting on chemical composition, physicochemical properties, and in vitro digestibility and intestinal iron absorption
2023, Food Research International
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The roasting conditions used in this study appeared to retain the nutritional composition of unroasted AS species. The in vitro PD was evaluated as the DH, since the two factors are known to have a positive correlation (Dimes et al., 1994). The DH in the raw AS flour ranged from 14.0 to 20.7 % (Fig. 1a).
Acacia seed (AS) is rich in protein and iron but contains protease inhibitors that can reduce protein digestibility (PD). The seeds are generally roasted prior to consumption, although no information on the PD of roasted AS is available. This study investigated the effect of roasting time (5, 7 and 9 min at 180 °C) on the chemical composition, physicochemical properties, and in vitro PD and intestinal iron absorption of three wild harvested Australian AS species, Acacia victoriae, A. coriacea and A. cowleana. Roasting A. victoriae and A. coriacea seeds for 7 min significantly increased PD in the seeds by 36 and 61 %, respectively. A 9-min roasting time was required to achieve 75 % reduction in trypsin inhibitor activity in A. coriacea seed, while a shorter roasting time (RT) was sufficient to achieve similar reduction rates in the other two Acacia species. Among the functional properties, water and oil absorption capacities were significantly enhanced as RT increased. The starch granules in 7- and 9-min roasted A. victoriae seed flour detached from the protein matrix while random coil increased in 7-min roasted A. victoriae and 9-min roasted A. coriacea and A. cowleana, thus, contributing to enhanced PD. Although the SDS-PAGE in 7- and 9-min roasted A. cowleana samples showed reductions in the intensity of bands for high molecular weight proteins, PD was not affected by RT. However, intestinal iron absorption was not significantly affected by roasting as compared to raw digesta samples. Compared to commercial roasted Acacia seed, the considerably shorter RT used in this study improved PD in the AS flour with less adverse effects on techno-functional properties.
Trypsin inhibitor reduction improves the utility of soy protein concentrate from soymilk in the diet of the juvenile red sea bream, Pagrus major
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However, the optimal nutritional potential of plant-derived protein can be achieved through appropriate processing by reducing or inactivating ANFs (Van der Ingh et al., 1991). As mentioned earlier, among the ANFs, fish are more sensitive to dietary TIs than terrestrial animals (Dimes et al., 1994), and red sea bream is more sensitive than some other commercially important species in Japan (Takii et al., 1998). Therefore, it was assumed that the higher replacement level (70%) of FM protein by SPC in the diet of juvenile red sea bream (Biswas et al., 2019) than the level reported when using conventionally processed SBM (Biswas et al., 2007) was mainly due to the reduction of TI activity in SPC from soymilk.
A rearing study was undertaken to investigate whether trypsin inhibitor (TI) activity reduction in soy protein concentrate (SPC) derived from soymilk can afford more replacement of fish meal (FM) protein in the diet of juvenile red sea bream, Pagrus major. A diet containing 67% FM as the sole protein source was used as the control (C). SPC products with TI activities of 36, 21 and 13 TIU/mg sample were prepared. Approximately 80% of FM protein in diet C was replaced by a combination of SPC products and corn gluten meal (4:1) and referred to as T36, T21 and T13, respectively. Aqueous krill extract (KE) was added at 1% in diets T36, T21 and T13 and termed T36K, T21K and T13K, respectively. Phytase was supplemented at 1000 FTU/kg diet in all SPC-based diets. Each of seven diets was fed to a group of 20 fish (mean weight 19 g) in triplicate twice per day to apparent satiation for 10 weeks. The final mean weight (P = 0.001), specific growth rate (SGR) (P = 0.001) and feed efficiency (FE) (P = 0.002) were significantly lower in fish fed the T36 and T36K diets than in those fed the other diets. However, there were no significant differences in final mean weight (P = 0.088), SGR (P = 0.314) and FE (P = 0.829) in fish fed diets T21, T13, T21K and T13K compared to the control diet. Although there were no significant differences in the digestibility of protein (P = 0.076) and energy (P = 0.066) among the treatments, the productive values of protein (P = 0.002) and energy (P = 0.001) were significantly reduced in fish fed the T36 and T36K diets. In contrast, a significantly lower phosphorus (P) retention efficiency (P = 0.026) in fish fed the control diet resulted in significantly higher P discharge (P = 0.001) to the environment compared with diets T21, T13, T21K and T13K. There were no major variations in hematocrit level or plasma constituents among the treatments, except glutamic oxaloacetic transaminase (GOT) and triglyceride. The results suggest that the reduction in TI activity at ≤21 TIU/mg sample (≤9.66 TIU/mg diet) in SPC from soymilk made it possible to replace 80% of FM protein without affecting growth performance and health status. Moreover, a significant reduction in P discharge suggests that ecological benefits can be achieved through improving diet utility by reducing TI activity in SPCs derived from soymilk.
Diet analysis and evaluation
2022, Fish Nutrition
In the previous edition, this chapter was part of the diet formulation and manufacture chapter. In this edition, a separate chapter is devoted to the topic. There are two reasons for this change. First, alternative ingredients increasingly used in fish feeds are less familiar, so identifying appropriate chemical tests to assess quality of alternative ingredients is needed. Second, as fishmeal levels in feeds are being reduced, fish feeds must be formulated to more precisely meet nutritional needs of fish, i.e., precision formulation. This makes it crucial to have tools to assess quality of feeds and ensure that available levels of essential nutrients are provided. The first portion of the chapter explains which chemical tests are appropriate to use to measure ingredient quality. Different ingredients present different potential quality problems. Interpretation of the results of chemical testing allows feed producers to select high-quality ingredients. In addition to chemical tests, microscopic examination of feed ingredients, somewhat of a lost art, is a valuable tool to detect adulteration of ingredients or heat damage. In the second portion of the chapter, in vivo methods of diet evaluation are presented. This includes digestibility measurements and calculations, feeding trials and their evaluation, and approaches to assess effects of diet on fish quality and safety to consumers. Finally, approaches used for economic evaluation of feeds are discussed.
Successful nursing of Mekong giant catfish (Pangasianodon gigas, Chevey 1930) larval by replacing live feed with microcapsule diet
2021, Aquaculture
The larviculture of Mekong giant catfish (Pangasianodon gigas, Chevey 1930) solely relies on live feeds.This study aimed to investigate the proper time to replace live feeds with a microcapsule diet (MC diet) in the earliest stage of larvae to reduce dependency on live feeds in larval rearing of Mekong giant catfish. Crude enzyme of the 3-dph (days post hatching), 7-dph, 14-dph, and 30-dph larvae were extracted for determination of proteolytic digestive enzyme activities. Specific activities of total protease, chymotrypsin-like and trypsin-like of larvae displayed an elevated tendency with increasing life stage of larvae. The highest specific activities of all digestive enzymes were noticed at 30 dph (p < 0.05). In vitro protein digestibility of fish protein hydrolysate (FPH) and fish meal digested by different-stage larval extracts showed that protein digestibility of both ingredients significantly increased with increasing life stage of the larvae (p < 0.05). Protein digestibility of FPH was significantly higher than that of fish meal at 3 dph, 7 dph, and 14 dph (p < 0.05). The highest protein digestibility of both ingredients were statistically observed in 30-dph larvae (p < 0.05). The results of in vitro experiments indicate that the metamorphosis of digestive system of larvae, which begins after 14 dph, is a suitable time to firstly introduce an inert diet for this catfish larval nursing. In a 28-day feeding exper TITLE \* MERGEFORMAT iment, 15-dph catfish larvaewere fed under three different feeding regimes including: Group A (live feed as a control) hand fed with Moina spp. from 15 dph to 42 dph; Group B (Moina and then MC diet) fed with Moina as a live feed and then MC diet from 15 dph to 27 dph and switched to MC diet as an inert diet from 28 dph to 42 dph; and Group C (MC diet) fed with MC diet from 15 dph up to 42 dph. They were fed three times daily for 28 days. The results showed improvement in weight gain rate and specific growth rate of catfish in Group B were comparable to that Group C fed with MC diet alone (p < 0.05). No significant difference in survival rate among the treatments was found (p > 0.05). Feeding MC diet did not cause any histopathological alterations in liver and intestine of catfish. In conclusion, early introduction of catfish larvae with MC diet alone can start at 30 dph, which helps in shortening Moina feeding period, providing growth rate and survival rate benefits.
Microwave treatment increased protein digestibility of pigeon pea (Cajanus cajan) flour: Elucidation of underlying mechanisms
2020, Food Chemistry
Citation Excerpt :
Significant differences were defined at a 5% level (P < 0.05). Protein digestibility was evaluated as the degree of hydrolysis, since the two parameters are well accepted to have a positive correlation (Dimes et al., 1994). As shown in Fig. 1, only microwave treatment significantly improved the DH of the isolated pigeon pea proteins (71.6 ± 4.2%) compared to the control (54.4 ± 2.5%, P < 0.05).
Pigeon pea is rich in proteins but has low protein digestibility like other legumes. This work investigated the effects of processing, including soaking, grinding, ultrasound and microwave, on the protein digestibility of pigeon pea flour. Only microwave treatment significantly increased in vitro protein digestibility from 54.4 ± 2.5% to 71.6 ± 4.2%. SDS-PAGE showed that the most abundant proteins in all samples were the 7S vicilin subunits. After microwave treatment, the starch granular structures of pigeon pea flour changed to clusters, and protein secondary structures lost 5% β-sheet and gained 5% random coil, which contributed to the increased protein digestibility. Microwave decreased protein water solubility from 94.4 ± 0.8% to 48.1 ± 6.5% and increased the disulfide bond content by 42%. The increased protein digestibility is attributable to the relatively reduced particle size (166.6 ± 38.6 nm) and increased zeta potential (−35.2 ± 2.6 mV) of the microwave-treated sample. Therefore, microwave is a promising approach for increasing pigeon pea flour protein quality and utilisation.
In vitro digestion method to evaluate solubility of dietary zinc, selenium and manganese in salmonid diets
2020, Journal of Trace Elements in Medicine and Biology
Citation Excerpt :
Castillo-Lopez and co-workers have used a digestion period of 240 min and samples were collected gradually during this period. In several studies digestive enzymes have been extracted from the intestinal tract of salmonids and used in the digestion experiments [5,6,9,19,26]. One advantage of using this enzyme extract is the higher comparability of the results obtained in vitro and in vivo [26,27].
The determination of dietary mineral solubility is one of the main steps in the evaluation of their availability for a given species.
This study proposed an in vitro digestion method (acidic and alkaline hydrolysis). The method was applied to evaluate the solubility of inorganic and organic forms of zinc (Zn), selenium (Se) and manganese (Mn) in salmonid diets. An inorganic mineral (IM) diet was supplemented with zinc sulphate, sodium selenite and manganous sulphate and an organic mineral (OM) diet was supplemented with zinc chelate of glycine, l-selenomethionine and manganese chelate of glycine.
The solubility of Zn was similar in both diets tested. The amount of soluble Zn was low in the acidic hydrolysis (3–8%) and lower in the alkaline hydrolysis (0.4–2%). The solubility of Se was higher in the OM diet (7–34%) compared with the IM diet (3–12%). Regarding Mn, after the acidic hydrolysis the solubility was higher in the IM diet (6–25%) than the OM diet (4–17%). The in vitro solubility were compared with in vivo availability of Zn, Se and Mn. Data obtained for solubility (%) of Zn, Se and Mn was lower when compared with apparent availability (%) of Zn, Se and Mn.
Data obtained demonstrated that solubility of Zn, Se and Mn was influenced by the mineral chemical form supplemented to the diet and by the gastrointestinal environment. The solubility of Zn, Se and Mn was not comparable with the apparent availability of Zn, Se and Mn. Nevertheless, the effect of the chemical form of the minerals was similar for the solubility of Zn, Se and Mn and the apparent availability of Zn, Se and Mn. Considering the overall results of this study, the in vitro method could replace some of the in vivo studies for a qualitative evaluation but not for a quantitative evaluation.

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Comparative Biochemistry and Physiology Part A: Physiology

Abstract

References (16)

Estimation of protein digestibility—I. Development of an in vitro method for estimating protein digestibility of salmonids (Salmo gairdneri.

Comp. Biochem. Physiol.

The preparation and properties of two new chromogenic substrates of trypsin

Archs. Biochem. Biophys.

An in vitro method for measuring protein digestibility of fish feed components

Aquaculture

The nutritional properties of co-dried fish silage in rainbow trout (Salmo gairdneri) dry diets

Aquaculture

Pancreatic proteinases from man, trout, rat, pig, cow, chicken, mink and fox. Enzyme activities and inhibition by soybean and lima bean proteinase inhibitors

Comp. Biochem. Physiol.

Protein measurement with the Folin phenol reagent

J. Biol. Chem.

Techniques for evaluation of dietary protein quality for the rainbow trout (Salmo gairdneri)

Aquaculture

Problems in the development and application of rapid methods of assessing protein quality

Food Technol.

Cited by (48)

Nutritional and techno-functional properties of Australian Acacia seed flour: Effects of roasting on chemical composition, physicochemical properties, and in vitro digestibility and intestinal iron absorption

Trypsin inhibitor reduction improves the utility of soy protein concentrate from soymilk in the diet of the juvenile red sea bream, Pagrus major

Diet analysis and evaluation

Successful nursing of Mekong giant catfish (Pangasianodon gigas, Chevey 1930) larval by replacing live feed with microcapsule diet

Microwave treatment increased protein digestibility of pigeon pea (Cajanus cajan) flour: Elucidation of underlying mechanisms

In vitro digestion method to evaluate solubility of dietary zinc, selenium and manganese in salmonid diets