Inclusion of anti-phospholipase A2 antibody to backgrounding diets on performance, feed efficiency, in vitro fermentation, and the acute-phase response of growing beef calves

Exploring the potential effect of phospholipase A2 antibody to extend beef shelf-life in a beef liposome model system

The objective of this study was to elucidate the effect of phospholipase A2 (PLA2) and a PLA2 antibody (aPLA2) on phospholipid (PL) hydrolysis in beef and to understand how the altered PL composition may affect lipid oxidation and antioxidant capacity of beef in an in vitro system. Various combinations of PLA2 and aPLA2 were introduced to a beef liposome model system and exposed to a retail display. The PL and free fatty acid (FFA) profiles, antioxidant capacity and lipid oxidation were measured for the liposome system. Key PL classes were reduced and the release of polyunsaturated FFAs was increased with the inclusion of PLA2 in the treatments (P < 0.05). There was no inhibition of PL hydrolysis with the addition of aPLA2. PLA2 showed strong antioxidant capacity in the liposome system (P < 0.01), but lipid oxidation still increased in samples treated with PLA2 throughout the retail display (P < 0.01). Finally, aPLA2 treatments demonstrated potential to decrease lipid oxidation (P < 0.01).

Effects of anti-phospholipase A(2) antibody supplementation on dry matter intake feed efficiency, acute phase response, and blood differentials of steers fed forage- and grain-based diets

To determine whether supplementation of anti-phospholipase A antibody (aPLA) would alter voluntary DMI, feed efficiency (FE), acute-phase protein concentration, and blood differentials (BD) due to a change in diet from a forage-based to a grain-based diet, individual daily DMI was measured on 80 cross-bred steers during a 141-d period. On d 0, steers were blocked by BW and randomly assigned to receive a growing forage diet containing 1) no additive (CON; = 20), 2) inclusion of 30 mg of monensin and 8.8 mg of tylosin per kg of diet DM (MT; = 20), 3) inclusion of an aPLA supplement at 0.4% of the diet DM (0.4% aPLA; = 20), and 4) inclusion of an aPLA supplement at 0.2% of the diet DM (0.2% aPLA; = 20). On d 60, steers were transitioned into a grain-based diet (90% concentrate) over a 21-d "step-up" period while continuing to receive their supplement treatments and were maintained on the high-grain diet until the end of the trial on d 141. On d 0, 60, 81, and 141, individual shrunk BW was recorded. Blood samples were collected on d 60, 63, 65, 67, 70, 72, 74, 77, 79, 81, and 84 for determination of concentration of plasma ceruloplasmin, haptoglobin, and BD. During the growing forage-diet period, steers from the 0.2% aPLA and 0.4% aPLA treatments had lower ( < 0.05) residual feed intake (RFI; -0.12 ± 0.13 and -0.22 ± 0.13 kg/d, respectively) than steers from the CON treatment (0.31 ± 0.13 kg/d). During the grain-based diet period, the 0.2% aPLA (-0.12 ± 0.10 kg/d), 0.4% aPLA (0.36 ± 0.10 kg/d), and MT (0.10 ± 0.10 kg/d) steers had greater ( = 0.04) RFI than CON steers (-0.37 ± 0.10 kg/d). During the transition phase, white blood cell counts were greater ( = 0.04) for the 0.2% aPLA treatment (13.61 × 10 ± 0.42 × 10 cells/μL) than the 0.4% aPLA and MT treatments (12.16 × 10 ± 0.42 × 10 and 12.37 × 10 ± 0.42 × 10 cells/μL, respectively) and concentrations of lymphocytes also were greater ( = 0.01) for the 0.2% aPLA treatment (7.66 × 10 ± 0.28 × 10 cells/μL) than the 0.4% aPLA and MT treatments (6.71 × 10 ± 0.28 × 10 and 6.70 × 10 ± 0.28 × 10 cells/μL, respectively). Concentrations of plasma ceruloplasmin and haptoglobin were reduced ( < 0.05) for CON compared to aPLA steers (22.2 ± 0.83 vs. 24.4 ± 0.83 mg/dL and 0.18 ± 0.05 vs. 0.26 ± 0.05 mg/mL, respectively). Supplementation of aPLA improved FE of steers fed a forage-based growing diet but not when feeding grain-based diets. The 0.4% aPLA and MT treatments had decreased white blood cell counts and concentration of lymphocytes during the transition period compared to the 0.2% aPLA treatment, and CON steers had reduced concentrations of plasma ceruloplasmin and haptoglobin during the diet transition phase.