Effects of supplementation of boric acid into feed and drinking water on performance, intestinal microbiota and histopathology in different quail varieties (Coturnix coturnix Japonica)

There were two trial layouts in this study. In Experiment-I, egg yield, egg quality characteristics, hatching performance, intestinal total lactic acid and colifom bacterial load of boric acid added to feed and water in different quail varieties (Coturnix coturnix Japonica) were determined. In Trial-II, the possibility of using different doses of boric acid as an alternative to antibiotics in quails with experimental infection was investigated, and its effects on intestinal histopathology and blood biochemistry were determined. For Trial-I, 300 laying quails in yellow, white, gray and black were used. Supplementation groups; (Y100): 100 mg/kg boric acid was added to the feed, (Y300): 300 mg/kg boric acid was added to the feed, (S100): 100 mg/kg boric acid was added to the drinking water, (S300): 300 mg/kg boric acid was added to the drinking water, and control (no supplementation). There were 4 female+1 male x 3 replications total of 15 quails in each color group. Each additive group included 15 x 4 colors, a total of 60 quails. Trial-I lasted 90 days. At the end of Trial-I, the 40 male quails were slaughtered and intestinal samples were taken and bacterial load was examined. Groups of the Trial-II; Control (G1), Infected (G2), Infected+Antibiotic (G3), Infected+Boric acid in drinking water (100 mg/L) (G4), Infected+Boric acid in drinking water (300 mg/L) (G5), Infected+Boric acid in feed (100 mg/kg) (G6), Infected+Boric acid in feed (300 mg/kg) (G7). In this experimental group, the 84 quails were used. As a result of the experimental infection, the quails were fed with feed and water for one week, and at the end of the experiment, all quails were slaughtered and blood and intestinal samples were sampled. Addition of boric to water and feed had no effect on egg production, feed consumption, feed efficiency, viability and water consumption (P>0.05). Egg shell properties were best found in the Y100 group (P<0.001). In the Y300 group, hatchability (P<0.05) and hatchability of fertile eggs increased (P<0.01), while embryo mortality decreased (P<0.01). Compared to the control, the total lactic acid bacteria count increased in all boron groups, and the coliform bacteria count decreased significantly in the Y300, S100 and S300 groups (P<0.001). Egg production, feed efficiency, viability, hatchability and intestinal total bacterial load parameters were similar in different varieties (P>0.05). Feed consumption was highest in yellow and gray genotypes (P<0.001). Considering the external egg quality characteristics, yellow and white genotypes were found to be superior (P<0.001). Egg shell thickness was significantly lower in gray genotype than in other color groups (P<0.001). In Trial II, although the severity of the inflammation in the infection group, certain levels of enteritis were observed in all groups, and boric acid had a positive effect on the inflammation parameters. The highest white blood cell level was found in the infection group and the lowest in the control group (P<0.05), and similar values were obtained in the antibiotic and additive groups (P>0.05). There was no statistical difference in lymphocyte, monocyte, granulocyte levels and proportional values (P>0.05). As a result, it was determined that boric acid can be used as an additive in terms of egg shell quality, hatchability performance and intestinal health, and quail genotypes were found to be generally similar in terms of examined features.