Effects of Different Sources and Levels of Zinc on Growth Performance, Nutrient Digestibility, and Fur Quality of Growing-Furring Male Mink (Mustela vison)

Counteract severe heat stress by including different forms of zinc in the rabbit bucks' diet

The harmful influences of global warming on rabbit reproduction and industry attract global attention. Zinc (Zn) is an important trace element with a wide list of functions in the male reproductive system. The aim of this study was to estimate the effects of different forms of zinc supplementation, as organic (Zn methionine), nano (nano Zn oxide) as indirect way to minimized it impact on environment, and inorganic (Zn sulphate) on physiological parameters, semen quality, anti-oxidative status, hormonal profiles of male rabbits subjected to server heat stress. Thirty-six V-line bucks (6-7 months old, 2842.29 ± 34.46 g weight) were randomly distributed to 4 groups, bucks in 1st group (control group, Con) fed basal diet without Zn supplementation, the 2nd, 3rd and 4th groups fed basial diet with 30 mg/kg of zinc methionine (Zn-Met), nano zinc oxide (ZnO-NPs), and zinc sulphate (Zn-S), respectively for a period of 10 weeks suffered from severe heat stress of environmental ambient temperature (over 32 of temperature humidity index, THI). Semen samples were collected and evaluated for volume, pH, motility, concentration, viability, initial fructose, and seminal plasma antioxidant concentration. Liver, kidney function, hormonal and antioxidant profile were measured in blood serum. The results revealed that, compared to control, all forms of Zn supplementation used significantly improved kidney function (creatinine), serum antioxidant (SOD and CAT), physiological parameters, especially on 1st month of the experiment, and seminal plasma antioxidant (SOD and CAT) of heat stressed bucks. Likewise, semen quality in terms of sperm concentration, sperm viability, and initial fructose enhanced significantly (P ≤ 0.05) by ZnO-NPs supplementation. Zinc methionine supplementation significantly improved liver function and decreased seminal plasma TBARs. Treatments with Zn-Met and ZnO-NPs increased seminal TAC and blood testosterone levels with reduced blood cortisol levels compared to other groups. Severe heat stress could be counteract by inclusion Zn with studied forms Zn-Met and ZnO-NPs at recommended dose (30 mg/kg diet) to improve semen quality and antioxidant status.

A mink (Neovison vison) model of self-injury: Effects of CBP-CREB axis on neuronal damage and behavior

Objective

Self-injurious behavior (SIB) is a clinically challenging problem in the general population and several clinical disorders. However, the precise molecular mechanism of SIB is still not clear. In this paper, the systematic investigation of the genesis and development of SIB is conducted based on behavioral and pathophysiology studies in mink (Neovison vison) models.

Method

The night-vision video was used to observe the mink behavior, and the duration was a month. HE stain was performed to characterize the pathology change in the brain of a mink. IHC assay was performed to conduct the protein level detection of Iba-1, p-CREB, CBP, and p300 in the brain tissues. Elisa assay was used to examine the levels of NfL and NfH in serum and CSF of mink. The qRT-PCR assay was used to detect the expression of Bcl-2, NOR1, FoxO4, c-FOS, CBP, and p300 in brain tissues. Western blot was used to detect the protein levels of p-CREB, CBP, and p300 in brain tissues. We also used Evans Blue as a tracer to detect whether the blood-brain barrier was impaired in the brain of mink.

Result

The behavioral test, histopathological and molecular biology experiments were combined in this paper, and the results showed that CBP was related to SIB. Mechanism analysis showed that the dysregulation of CBP in brain-activated CREB signaling will result in nerve damage of the brain and SIB symptoms in minks. More importantly, the CBP-CREB interaction inhibitor might help relieve SIB and nerve damage in brain tissues.

Conclusion

Our results illustrate that the induction of CBP and the activation of CREB are novel mechanisms in the genesis of SIB. This finding indicates that the CBP-CREB axis is critical for SIB and demonstrates the efficacy of the CBP-CREB interaction inhibitor in treating these behaviors.

Effect of source and concentration of zinc on growth performance, meat quality and mineral retention in New Zealand rabbits

<p>Zinc supplementation in rabbit diet favours deposition of this mineral in meat and, therefore, contributes to satisfying the daily requirements of Zn in humans that consume it. A trial was conducted to study the effect of two sources (ZnSO₄ and Zn-methionate) and two concentrations of Zn, along with a control (without Zn supplementation), on weight gain, meat quality and muscle retention in New Zealand White (NZW) rabbits during fattening stage. Treatments were randomly assigned to 100 NZW rabbits 40 days old, in a completely randomised experimental design using a factorial arrangement of treatments (2×2+control). The experimental period was 30 d. In each experimental treatment, weight gain, feed consumption and meat quality were recorded, as well as the retention of Zn in serum, liver, loin and hind leg. Results showed no differences (<em>P</em>&gt;0.05) in weight gain and food consumption, which can be attributed to diet-added Zn sources (ZnSO₄ and Zn-methionate). Food conversion was better with the organic source at the highest concentration (<em>P</em>&lt;0.05). Regarding meat quality, no differences were found (<em>P</em>&gt;0.05) in hind legs for source effect and Zn concentration, while in loin, differences (<em>P</em>=0.02) were found in the colour parameter of L* and B* when the organic source of Zn (Zn-methionate) was supplied. Most retention of Zn on the loin occurred when a concentration of 25 mg Zn kg^–1 of Zn-methionate was added, which could be important to provide larger amounts of Zn for human consumption.</p>