Abomasal amino acid infusion in postpartum dairy cows: Effect on whole-body, splanchnic, and mammary amino acid metabolism

Abstract

Nine Holstein cows with rumen cannulas and indwelling catheters in splanchnic blood vessels were used in a generalized randomized incomplete block design with repeated measures to study the effect of increased early postpartum AA supply on splanchnic and mammary AA metabolism. At calving, cows were blocked according to parity (second and third or greater) and allocated to 2 treatments: abomasal infusion of water (CTRL; n=4) or free AA with casein profile (AA-CN; n=5) in addition to a basal diet. The AA-CN infusion started with half of the maximal dose at the calving day (1 d in milk; DIM) and then steadily decreased from 791 to 226 g/d until 29 DIM. On 5, 15, and 29 DIM, 6 sample sets of arterial, portal, hepatic, and mammary blood were taken at 45-min intervals. Over the whole period, increasing AA supply increased milk (+7.8 ± 1.3 kg/d) and milk protein yields (+220 ± 65 g/d) substantially. The increased milk yield was not supported by greater dry matter intake (DMI) as, overall, DMI decreased with AA-CN (-1.6 ± 0.6 kg/d). Arterial concentrations of essential AA were greater for AA-CN compared with CTRL. The net portal-drained viscera (PDV) release of His, Met, and Phe was greater for AA-CN compared with CTRL, and the net PDV recovery of these infused AA ranged from 72 to 102% once changes in DMI were accounted for. The hepatic removal of these AA was increased equivalently to the increased net PDV release, resulting in an unaltered net splanchnic release. The net PDV release of Ile, Leu, Val, and Lys tended to be greater for AA-CN, and the net PDV recovery of these infused AA ranged from 69 to 73%, indicating increased PDV metabolism with AA-CN. The fractional hepatic removal of these AA did not differ from zero and was unaffected by the increased supply. Consequently, the splanchnic release of these AA was approximately equivalent to their net PDV release for both CTRL and AA-CN. Overall, greater early postpartum AA supply increased milk and milk protein yields substantially based on increased mammary AA uptake. The PDV metabolism of branched-chain AA and Lys were increased, whereas it seemed to be unaffected for other essential AA when the intestinal AA supply was increased. On a net basis, the liver removed more group 1 AA (His, Met, Phe, and Trp) for anabolism and catabolism when the early postpartum AA supply was increased. Thus, increasing the postpartum AA supply increased splanchnic and mammary consumption of AA; hence, the protein deficiency persisted.

Mammary gland utilization of amino acids and energy metabolites differs when dairy cow rations are isoenergetically supplemented with protein and fat

“…Although the absolute values for U:O for the group 1 AA and for total AA indicate some discrepancy on the whole, the relative differences in response to PT 5 (no effect on the total group 1 AA, increased group 2 AA) align with other studies performing mammary AA net balance under conditions of supplemental MP (Raggio et al, 2006;Haque et al, 2015). Previous mammary balance studies have produced total AA balances greater than or equal to unity (Raggio et al, 2006;Doepel and Lapierre, 2010), but some studies present values near 0.90 (Larsen et al, 2014(Larsen et al, , 2015, with values ranging from 0.83 to 0.96 within a study (Larsen et al, 2014). Furthermore, in the current study, when U:O for total AA was calculated on an N basis, the ratio increased to 0.85, 0.91, 0.93, and 0.88 for LP/LF, HP/ LF, LP/HF, and HP/HF, respectively.…”

Ruminal microorganism consideration and protein used in the metabolism of the ruminants: A review

“…Infusions of casein in the abomasum or intestine, increases the milk production (Chalupa and Sniffen, 1991;Larsen et al, 2015;Hills et al, 2015). However, in Brazil according to Santos and Greco (2007) from 127 compared 88 experiments with cows in milk production, where the soybean meal was replaced partly or wholly by RUP rich sources, have concluded that only 17% of cows showed an increase in milk production due to the processing of soybean meal.…”

Changes in tissue abundance and activity of enzymes related to branched-chain amino acid catabolism in dairy cows during early lactation

“…In this regard, degradation of BCAA (transamination or oxidative decarboxylation of 3557 the transamination products) has been studied in different tissues of ruminants, including the digestive tract (Pell et al, 1986;MacRae et al, 1997), liver , muscle (Pell et al, 1986;Bequette et al, 2002), and MG (Bequette et al, 1996a,b;Thivierge et al, 2002). However, previously published data on BCAA net fluxes and isotopic tracer studies in dairy cows have shown that, quantitatively, hepatic removal of BCAA (and their metabolites) is limited, as is their oxidation Raggio et al, 2004;Larsen et al, 2015).…”