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Whey protein gel composites in the diet of goats increased the omega‐3 and omega‐6 content of milk fat
Author(s) -
Weinstein J. A.,
Taylor S. J.,
Rosenberg M.,
DePeters E. J.
Publication year - 2016
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/jpn.12374
Subject(s) - omega , food science , whey protein , chemistry , zoology , biology , physics , quantum mechanics
Summary Previously, feeding whey protein gels containing polyunsaturated fatty acids ( PUFA ) reduced their rumen biohydrogenation and increased their concentration in milk fat of Holstein cows. Our objective was to test the efficacy of whey protein isolate ( WPI ) gels produced in a steam tunnel as a method to alter the fatty acid ( FA ) composition of the milk lipids. Four primiparous Lamancha goats in midlactation were fed three diets in a 3 × 4 Latin square design. The WPI gels were added to a basal concentrate mix that contained one of three lipid sources: (i) 100% soya bean oil (S) to create ( WPI /S), (ii) a 1:1 (wt/wt) mixture of S and linseed (L) oil to create ( WPI / SL ), or (iii) 100% L to create ( WPI /L). Periods were 22 days with the first 10 days used as an adjustment phase followed by a 12‐day experimental phase. During the adjustment phase, all goats received a rumen available source of lipid, yellow grease, to provide a baseline for milk FA composition. During the experimental phase, each goat received its assigned WPI . Milk FA concentration of C18:2 n‐6 and C18:3 n‐3 reached 9.3 and 1.64 g/100 g FA , respectively, when goats were fed WPI /S. Feeding WPI / SL increased the C18:2 n‐6 and C18:3 n‐3 concentration to 6.22 and 4.36 g/100 g FA , and WPI /L increased C18:2 n‐6 and C18:3 n‐3 to 3.96 and 6.13 g/100 g FA respectively. The adjusted transfer efficiency (%) of C18:3 n‐3 to milk FA decreased significantly as dietary C18:3 n‐3 intake increased. Adjusted transfer efficiency for C18:2 n‐6 did not change with increasing intake of C18:2 n‐6. The WPI gels were effective at reducing rumen biohydrogenation of PUFA ; however, we observed a change in the proportion increase of C18:3 n‐3 in milk FA suggesting possible regulation of n‐3 FA to the lactating caprine mammary gland.