Prophylaxis of microelementosis in rabbits using a mixture of glauconite, succinic, humic and fulvic acids and minerals

Impaired metabolism of mineral substances in the conditions of industrial rabbit breeding may cause decrease in increment of live mass, reduction of immunity, mass morbidity and death of animals. In our experiment, we studied the efficiency of using a mineral mixture to prevent the disorders in the metabolism of rabbits according to changes in morphologic, biochemical parameters and antioxidant status of blood, chemical composition of blood plasma and increments in body weight compared to the control group of animals. For the studies, we formed four groups of white New Zealand rabbits, each comprising six individuals aged 70 days with mean body weight equaling 1.99 kg. In group I, the rabbits received an aqueous form of a mixture of glauconite, succinic acid, humic and fulvic acids and lactates of zinc, manganese, cuprum, cobalt and iron with water, rabbits of group II were given a dry form of a mixture of glauconite, succinic acid, humic and fulvic acids and lactates of zinc, manganese, cuprum, cobalt and iron with fodder, and the rabbits of group III were intramuscularly injected with butanol fraction of humic acids. The experiment lasted for 21 days. The results of the experiment indicate that the most effective prophylaxis of malfunctions of mineral metabolism in white New Zealand rabbits aged 70–95 was dry mixture of glauconite, succinic acid, humic and fulvic acids and lactates of zinc, manganese, cuprum, cobalt and iron with fodder (group II), which was given once a day for 21-day period. We determined a positive effect of biologically active supplement on the parameters of hematopoiesis(1.25 times significantly higher level of hemoglobin and 1.14 times higher number of erythrocytes), metabolism of proteins (1.54 times significantly higher content of albumins), mineral substances (significantly higher content of inorganic phosphorus – by 1.17 times, calcium by 2.18 times, manganese by 1.39 times, zinc by 1.50 times, iron by 1.39 times and cuprum by 1.49 times), functional condition of the liver (2.04 times lower activity of gamma-glutamyltransferase), the state of the antioxidant system (lowest catalase activity) and energy of rabbits’ growth (1.20-fold increment in body weight). The results of our study indicate that using a dry form of the mixture of glauconite, succinic acid, humic and fulvic acids and lactates of zinc, manganese, cuprum, cobalt and iron with fodder is an efficient method of preventing malfunctioning of mineral metabolism in rabbits.

Effect of dietary supplementation with insect fats on growth performance, digestive efficiency and health of rabbits

BACKGROUND

The present work aimed at evaluating the effect of the dietary replacement of soybean oil (S) by two types of insect fats extracted from black soldier fly larvae (H, Hermetia illucens L.) and yellow mealworm larvae (T, Tenebrio molitor L.) on growth performance, nutrient digestibility, blood parameters, intestinal morphology and health of growing rabbits.

METHODS

At weaning, 200 crossbred rabbits (36 days old) were allotted to five dietary treatments (40 rabbits/group): a control diet (C) containing 1.5% of soybean oil and four experimental diets where soybean oil was partially (50%) or totally (100%) substituted by H (H50 and H100) or T (T50 and T100) fats. Total tract digestibility was evaluated on 12 rabbits per treatment. The growth trial lasted 41 d and, at slaughtering (78 days old), blood samples were collected from 15 rabbits per treatment, morphometric analyses were performed on duodenum, jejunum and ileum mucosa, and samples of liver, spleen and kidney were submitted to histological evaluation.

RESULTS

No difference was observed between the control and the experimental groups fed insect fats in terms of performance, morbidity, mortality and blood variables. The addition of H and T fats did not influence apparent digestibility coefficients of dry matter, protein, ether extract, fibre fractions and gross energy. Gut morphometric indices and organ histopathology were not affected by dietary inclusion of H and T fats.

CONCLUSIONS

H and T fats are suitable sources of lipid in rabbit diets to replace soybean oil without any detrimental effect on growth performance, apparent digestibility, gut mucosa traits and health.

The effect of different dietary zinc sources on mineral deposition and antioxidant indices in rabbit tissues

<p>The purpose of this study was to compare the effect of dietary zinc from inorganic and organic sources on the concentration of Zn, Cu, Mn and Fe in plasma, tissues and faeces of rabbits. Simultaneously, the activities of total superoxide dismutase (SOD), specific Cu/Zn SOD, glutathione peroxidase (GPx), lipid peroxidation and total antioxidant capacity (TAC) in liver and kidney were also determined. Ninety-six 49-day-old broiler rabbits were allocated to 4 dietary treatments, each replicated 6 times with 4 animals per replicate. For the subsequent 6 wk, the rabbits were fed an identical basal diet (BD) supplemented with an equivalent dose of Zn (100 mg/kg) from different sources. Group 1 (control) received the unsupplemented BD, while the BD for groups 2, 3 and 4 was supplemented with Zn from Zn sulphate, Zn chelate of glycine hydrate (Zn-Gly) and Zn chelate of protein hydrolysate (Zn-Pro), respectively. The intake of dietary Zn sulphate resulted in an increase in Zn plasma concentration (1.85 vs. 1.48 mg/L; <em>P</em>&lt;0.05) compared to the control group. Feeding the diets enriched with Zn increased the deposition of Zn in the liver (<em>P</em>&lt;0.05), irrespective of the Zn source. The addition of Zn-Pro resulted in significantly higher Cu uptake in liver (<em>P</em>&lt;0.05) than in the control and Zn sulphate group (56.0 vs. 35.0 and 36.7 mg/kg dry matter (DM), respectively). Neither Mn nor Fe concentration in plasma and tissues were affected by dietary Zn supplementation, with the exception of Fe deposition in muscle, which was significantly decreased (<em>P</em>&lt;0.05) in rabbits supplemented with inorganic Zn sulphate compared to control and Zn-Gly group (9.8 vs. 13.3 and 12.2 mg/kg DM, respectively). Intake of organic Zn-Gly significantly increased the activities of total SOD (43.9 vs. 35.9 U/mg protein; <em>P</em>&lt;0.05) and Cu/Zn SOD (31.1 vs. 23.8 U/mg protein; <em>P</em>&lt;0.01) as well as TAC (37.8 vs. 31.2 μmol/g protein; <em>P</em>&lt;0.05) in the kidney when compared to that of the control group. The presented results did not indicate any differences between dietary Zn sources in Zn deposition and measured antioxidant indices in rabbit tissues. Higher dietary Zn intake did not cause any interactions with respect to Mn, Cu and Fe deposition in liver and kidney tissues, but did increase the faecal mineral concentrations. Dietary organic Zn-Gly improved the antioxidant status in rabbit kidney.</p>