Plasmatic biochemical profile of lactating Holstein cows supplemented with chitosan and raw soybeans

The aim of this study was to evaluate the effect of chitosan (CHI) and raw soybeans (RSO)
addition in dairy cows diets on plasmatic biochemical profile. Twenty four Holstein cows
(140.7 ± 37.1 days in milk, 35.0 ± 5.4 kg/day of milk yield and 619.0 ± 81.1 kg of BW)
were used in a replicated 4 x 4 Latin square design with 23-d periods, with 15 d of
adaptation and 8 d for data collection. Treatments arrangement was a 2 x 2 factorial design
with two levels of CHI (0 and 4 g/kg of dietary DM) and two levels of RSO (0 and 140
g/kg of dietary DM). The forage source used was maize silage, accounting for 50% of diet
DM basis. Blood samples were collected on d 18 of each period, at zero and 4-h after the
morning feeding from the coccygeal artery or vein. Glucose, total protein, albumin, urea,
cholesterols (Chol; total-Chol; HDL-Chol; VLDL-Chol and LDL-Chol), triglycerides and
liver enzymes (aspartate aminotransferase-AST and glutamyl transferase-GGT)
concentrations were evaluated in serum. The data were analyzed using the MIXED
procedure of SAS and the means were adjusted by LSMEANS. No interactions were
observed (P>0.05) between CHI and RSO. RSO decreased (P<0.05) glucose (70.3 vs 71.8
mg/dL), total protein (8.15 vs 8.29 g/L) and urea (44.7 vs 46.5 mg/dL) concentrations, and
increased (P<0.01) total-Chol (188 vs 152 mg/dL), HDL-Chol (105 vs 95.3 mg/dL),
VLDL-Chol (2.83 vs 2.67 mg/dL), LDL-Chol (80.2 vs 54.4 mg/dL) and triglycerides (14.2
vs 13.3 mg/dL) concentrations. Probably the glucose decrease was due to the intake
decrease in RSO diets, leading to a minor propionate total flow in liver. The use of amino
acids for hepatic gluconeogenesis is the hypothesis for total protein concentration decrease.
Blood urea decreasing can be explained by it lower inclusion in the RSO diets. The
increased of triglycerides and cholesterols with raw soybean supplementation was justified
by the lipid intake increase. The AST, GGT and albumin concentrations were not affected
by raw soybeans supplementation (P>0.05). There was no effect of chitosan on blood
metabolic profile (P>0.05). In conclusion, the raw soybeans addition in dairy cows diets
induces plasmatic biochemical changes, especially on lipidogram and glucose
concentration.