Whey Protein Isolate Gels Fed to Jersey Cows to Protect Beta-Carotene from Rumen Degradation

Cow's milk has a low concentration of BC due in part to low BC concentrations in feedstuffs, limited absorption of BC in the intestines, and metabolism by and storage in tissues as well as a phenomenon not well understood where dietary BC appears to be degraded in the rumen. Previously, a whey protein isolate gel was demonstrated to be capable of increasing omega-3 concentrations in cow's milk by protecting the unsaturated fatty acids from biohydrogenation in the rumen. Our hypothesis was that the same technology if applied to BC would increase the BC concentration in the milk of Jersey cows. The objective of this study was to test the efficacy of a whey protein isolate gel to protect BC from rumen degradation and increase the BC concentration of Jersey milk. Four primiparous and four multiparous Jersey cows were fed a basal TMR (total mixed-ration) with a 500 mg BC supplement fed in two physical forms, either in a whey protein isolate gel (GEL) or as free, rumen available BC (CTL) in a crossover design. Periods were 21 days with a two-week interval between periods to minimize carryover effects. Beta-carotene concentrations were measured in blood plasma and milk. Feeding the GEL significantly increased in BC concentration in plasma 0.6620 mug/ml, but no significant increase in BC concentration occurred in milk. The WPI gel was effective in increasing the BC concentration of plasma, however a challenge still exists in transferring the BC into the mammary gland and its milk.