Adsa Logo White Adsa Title White

Plasma amino acid response to casein or acid casein hydrolysate in Holstein calves.

E. A. Petzel



Join E. A. Petzel on this page for a live text chat!
6:00 PM - 8:00 PM GMT


Plasma amino acid response to casein or acid casein hydrolysate in Holstein calves.
E. A. Petzel*, S. Acharya, E. A. Bailey, D. W. Brake. Division of Animal Sciences, University of Missouri Columbia, MO.

Previous reports in cows suggest that AA response to enzymatically hydrolyzed casein and casein are similar, but plasma AA concentrations in nonruminants increase in amount and rate to hydrolyzed protein compared with complete protein. Typically, degree of hydrolysis in enzymatically hydrolyzed casein is less than the degree of hydrolysis in acid hydrolyzed casein (AHC). We fed AHC and sodium caseinate (CAS) to 6 Holstein bull calves (initial BW = 54 � 1.4 kg) to compare bioavailability of AHC and CAS. Calves were provided either 0, 60, or 120 additional grams of AAs from either AHC or CAS added to a milk replacer (403.1 � 0.73 g DM) formulated to meet or exceed ME and Lys requirements of a 68 kg calf gaining 0.45 kg daily. Calves were adapted to treatments for 6 d and samples of jugular blood were collected each 4 h on d 7 to determine AA bioavailability. Each calf was provided each combination of treatments balanced for carryover effect. Plasma essential AA increased linearly (P < 0.01) with increasing intake of AHC and CAS, but rate of increase among plasma essential AA in response to greater intake of AHC and CAS was similar (P = 0.28). Branched-chain amino acids accounted for over 70% of increases in essential AA regardless of source of AA. Lysine tended to increase linearly in response to AHC (P = 0.06) while there were no changes in concentration of Thr or Trp in response to AHC or CAS (P ≥ 0.18). Concentrations of nonessential AA increased linearly with AHC (P < 0.01) but only tended to increase in response to CAS (P = 0.06). Rate of increase in nonessential AA to AHC was greater (1.42 �M/g AA) compared with CAS (0.62 �M/g AA, P = 0.02). Glutamate, Asp, Ala, Ser, and Pro increased at a greater rate (P ≤ 0.04) in AHC fed calves compared with calves fed CAS while Tyr, Asn, and His increased at a greater rate (P ≤ 0.04) in CAS compared with AHC. Plasma concentrations of Gly decreased (P = 0.01) with increasing sodium caseinate intake. Rate of increase in total plasma AA concentration in response to AHC tended (P = 0.11) to be 145% greater than CAS. These data seem to indicate that AA bioavailability it greater to AHC than to CAS in milk-fed calves.

Keywords: amino acid, bioavailability, casein.