Promising perspectives for ruminal protection of polyunsaturated fatty acids through polyphenol-oxidase-mediated crosslinking of interfacial protein in emulsions

Structural basis for high-pressure improvement in depolymerization of interfacial protein from RFRS meat batters in relation to their solubility

High-pressure processing (HPP) can modify the construction of interfacial proteins (IPs) to improve the properties of reduced-fat and reduced-salt (RFRS) meat batters. In this study, the relationship between the construction of IPs and their solubility at fat droplet/water interface in RFRS meat batters with HPP treatments was investigated. When 200 MPa for 2 min was applied, the IPs exhibited the highest solubility due to a high concentration of absorbed myosin with the content of random coil 65.62%, but the particle diameter was in reverse. The microscopy revealed the depolymerization of IPs occurred at low pressure, while macromolecular aggregates were produced as the cross-linking of IPs to some degree at pressure ≥ 200 MPa. This phenomenon was supported by the result of SDS-PAGE and the sulfhydryl of IPs. In conclusion, the HPP induced solubility alteration of IPs was achieved by modifying their construction through adjusting the secondary structures and regulating bond interactions.

Partitioning of Rumen-Protected n-3 and n-6 Fatty Acids is Organ-Specific in Growing Angus Heifers

Dietary polyunsaturated fatty acids (PUFA), especially n-3 and n-6 fatty acids (FA), play an important role in the regulation of FA metabolism in all mammals. However, FA metabolism differs between different organs, suggesting a distinct partitioning of highly relevant FA. For the present study in cattle, a novel technology was applied to overcome rumen biohydrogenation of dietary unsaturated FA. Angus heifers were fed a straw-based diet supplemented for 8 weeks with 450 g/day of rumen-protected oil, either from fish (FO) or sunflower (SO). The FA composition in blood and five important organs, namely heart, kidney, liver, lung, and spleen, was examined. In blood, proportions of polyunsaturated FA were increased by supplementing FO compared to SO. The largest increase of eicosapentaenoic acid (EPA) proportion was found with FO instead of SO in the kidney, the lowest in the lung. Docosahexaenoic acid (DHA) was increased more in the liver than in kidney, lung, and spleen. The heart incorporated seven times more EPA than DHA, which is more than all other organs and described here for the first time in ruminants. In addition, the heart had the highest proportions of α-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) of all organs. The proportions of polyunsaturated FA in the lung and spleen were exceptionally low compared to heart, liver, and kidney. In conclusion, it was shown that the response to FO in the distribution of dietary n-3 FA was organ-specific while proportions of n-6 FA were quite inert with respect to the type of oil supplemented.

Goats' Feeding Supplementation with Acacia farnesiana Pods and Their Relationship with Milk Composition: Fatty Acids, Polyphenols, and Antioxidant Activity

Simple Summary

The study aimed to describe the fatty acids, polyphenols, and antioxidant activity of goat’s milk from five different feeding systems: Grazing; conventional diet; and conventional diet supplemented with 10, 20, and 30 percent of Acacia farnesiana pods. Conventional diet showed the highest content of polyunsaturated fatty acids while grazing showed the healthiest fatty acid profile. Similarly, grazing and A. farnesiana boosted the polyphenol content. A. farnesiana pod meal inclusion in the goats’ diets increased the selective presence of bioactive compounds and the antioxidant activity of goat’s milk while cholesterol content was reduced.

Abstract

Background: Research efforts have focused on the evaluation of the bioactive quality of animal products (milk, cheese, meat, and other by-products) contrasting various feeding strategies coming from different ecological zones. The study aimed to describe the fatty acids (FA), polyphenols (P), bioactive compounds (BC), and antioxidant activity (AA) of goat’s milk. Methods: Dairy goats were fed with five systems: (1) Grazing; (2) conventional diet (CD); (3) CD + 10% of Acacia farnesiana (AF) pods; (4) CD + 20% AF; and (5) CD + 30% AF. The fatty acid profile, health promoting and thrombogenic indexes were calculated. Milk extracts were evaluated by HPLC to determent phenolic compounds (gallic, caffeic, chlorogenic, and ferulic acids, catechin, epicatechin, and quercetin). Antioxidant activity of goat’s milk extract was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), oxygen radical absorbance capacity (ORAC), and the ferric reducing antioxidant power (FRAP) assays. Results: Conventional diet showed the highest content of polyunsaturated fatty acids while grazing showed the best n-6:n-3 and the linoleic:alpha linolenic acid ratio. Similarly, grazing and AF boosted the polyphenol content. Conclusions: Acacia farnesiana inclusion in the goats’ diets increased the presence of bioactive compounds and the antioxidant activity while diminishing the cholesterol content of goat’s milk.