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The present study was undertaken for the production of encapsulated zinc and its evaluation in broiler chicken diet. The process of microencapsulation involved the use of polymers, gum arabic and maltodextrin with a maximum encapsulation of efficiency of 66%. Encapsulated material contained about 20% zinc oxide (ZnO) as core material following the freeze-drying process. One hundred and ninety-two-day-old broiler chicks were distributed in four groups in six replications having eight birds in each. The four groups comprised control (inorganic source of zinc), En-Zn-100 (encapsulated zinc at 100% of control), En-Zn-50 (encapsulated zinc at 50% of control), and Org-Zn-50 (Zn-methionine at 50% of control). The experiment was carried out for 35 days following standard management practices. The live weight gain, feed intake and FCR were comparable among groups. Plasma and muscle zinc (ppm) content was unaffected by the level or source of zinc supplementation. The zinc apparent ileal digestibility coefficient was significantly (P < 0.05) higher in En-Zn-50 fed groups, while crude protein digestibility was not affected by the level or form of Zn supplementation. Bone weight, length, and zinc content were comparable, and bone ash content was significantly different among the groups. Relative expression of ZnT2 was significantly upregulated in encapsulated zinc-fed groups. From the study, it could be concluded that supplementation of zinc either as encapsulated or organic form at 50% of inorganic source (ZnO) could be sufficient to maintain the growth performance, serum, tissue and bone mineral content in broiler chicken., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The study was conducted to assess nano zinc (ZnN) as a feed supplement with an aim to compare the supplemental dose of inorganic zinc (ZnI). ZnN was synthesized from 0.45 molar (M) zinc nitrate [Zn(NO 3 ) 2 .6H 2 O] and 0.9 M sodium hydroxide (NaOH) and was confirmed to be of ZnN by TEM-EDAX measurements. Wister albino rats (rats; 84, 53.6 ± 0.65 g) were divided into seven groups (4 replicate with 3 rats each) and given feed supplemented with zinc for 60 days with either of the following diets: (1) normal control (NC): basal diet (BD) + no supplemental Zn; (2) ZnI-25: BD + 25 mg/kg Zn from inorganic ZnO; (3) ZnN-25: BD + 25 mg/kg of ZnN; (4) ZnN-12.5: BD + 12.5 mg/kg of ZnN; (5) ZnN-6.25: BD + 6.25 mg/kg of ZnN; (6) ZnN-3.125: BD + 3.125 mg/kg of ZnN; (7) ZnN-50: BD + 50 mg/kg of ZnN. T 3 and insulin-like growth factor-1 (IGF-1) hormone levels were similar among groups (P > 0.05), whereas T 4 and testosterone were significantly affected, based on supplemented dose. Zn supplementation improved both cell-mediated and humoral immunity. However, both cell-mediated immunity at 24 h and humoral immunity were statistically similar in ZnI-25 and ZnN-6.25 groups. Superoxide dismutase 1 gene expression was found to be similar in all experimental groups. The vascular degeneration were found in liver tissues moderately in NC, mildly in ZnN-6.25 and ZnN-3.125 groups, and no observable changes were noticed in kidney and spleen tissues. However, there was a mild damage in intestinal epithelium of ZnN-25 group rats, hyperplasia of goblet cells, and moderate damage in intestinal villi were observed in ZnN-50 group rats. From the study, it can be concluded that ZnN at half the dose of ZnI showed similar or better responses in terms of immunity, SOD-1 expression, hormonal profiles, and the tissue architecture of vital organs in rats, i.e., 25 mg/kg of Zn from ZnI and 12.5 mg/kg of ZnN impacted similar biological responses like immunity, SOD-1 expression, hormonal profiles, and the tissue architecture of vital organs in rats., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The trial was aimed at evaluating probable superiority, if any of nano zinc (NZn) over inorganic zinc (Zn) on immunity, serum minerals and T 3 , T 4 , and IGF-1 hormone profiles in goats. NZn was synthesized by using 0.45 M aqueous solution of Zn nitrate and 0.9 M aqueous solution of sodium hydroxide (average particle size 74 nm). Twenty-four male goats were grouped into four groups as per their body weight and were supplemented with either a basal diet with concentrate and straw at 50:50 ratio (Negative control, NC) alone or supplemented with 50 mg/kg Zn (Control) from inorganic Zn source, that is ZnO (IZn-50), 50 mg/kg Zn from NZn (NZn-50) or 25 mg/kg Zn from NZn (NZn-25). No change was observed in thyroid hormone status on zero and 90th day of experimental feeding, but NZn supplementation improved (p < 0.05) IGF-1 level on 90th day serum samples. Zn supplementation improved the humoral immunity in all the groups irrespective of the source. Similarly, cell-mediated immunity (CMI) measured by skinfold thickness after injecting Con-A, was also improved in Zn supplemented groups than control at 6, 12 and 48 h of incubation. NZn-50 animals showed highest HI (haemagglutination inhibition) titre as well as skin thickness. The CD 4 + (cluster of differentiation in %) was more (p < 0.05) in Zn supplemented groups. NZn-50 showed higher (p < 0.05) CD 8 + count than NC and similar (p > 0.05) to IZn-50 and NZn-25 groups without affecting (p > 0.05) the ratio of CD 4 + , CD 8 + among the treatment groups. Thus, NZn supplementation at 25 mg/kg had similar immunity and serum T 3 , T 4 and IGF-1 profiles compared with IZn at 50 mg/kg dose., (© 2021 Wiley-VCH GmbH.)

A study was conducted to validate the effects of nano form of zinc (NZn) on nutrient digestibility, zinc retention, organ and serum zinc profile, and hepatic metallothionein gene expression in Wistar albino rats (WAR). Nano zinc (NZn) was synthesized through chemical method, by using 0.45 M zinc nitrate [Zn(NO 3 ) 2 .6H 2 O] and 0.9 M sodium hydroxide (NaOH). The NZn particle in its oxide form was characterized by TEM-EDAX and XRD, and found to be in nano range (below 100 nm. Zinc was supplemented to the Wistar albino rats (WAR) through synthetic semi-purified diet either without Zn, or as inorganic zinc (IZn; 25 mg/kg), or as synthesized NZn (25, 12.5, 6.25, 3.125 or 50 mg/kg DM) for 60 days. The zinc content was observed to be significantly (P < 0.05) higher in liver, bone, kidney, and serum due to NZn supplementation where NZn-50 had highest zinc content and control had the least, without affecting Fe, Mn, and Cu. NZn at 12.5 mg/kg group rats were either comparable or better than IZn at 25 mg/kg in terms of zinc retention, CP digestibility, zinc level in serum, liver, bone, and kidney suggesting its better bioavailability simultaneously also reduced fecal excretion of zinc to the environment. Metallothionein mRNA expression was upregulated in NZn at 25 mg/kg and NZn at 50 mg/kg than IZn at 50 mg/kg. Thus, in WAR, NZn at half of the ICAR recommendation (25 mg/kg DM) is as effective as inorganic zinc at 100% of recommended dose.

The uniqueness of Zn is that, it is the second most abundant trace element in the animal body but can't be stored in the body, thus regular dietary intake is required. Zinc oxide (ZnO) nanoparticles (NP) particles are being extensively used in paints, skin lotions pigments, food, electronics appliances, biological and pharmaceutical applications and many more. Zinc oxide nanoparticles are the specially prepared mineral salt having particle size of 1 to 100 nm. It promotes growth can act as antibacterial agent, modulates the immunity and reproduction of the animals. Both in lower and higher doses of specifications it has exhibited a variety of effects on animal performances. Apart from being highly bio-available, reports have already pointed out the growth promoting, antibacterial, immuno-modulatory and many more effects of nano zinc (nZn). These can be used at lower doses and can provide better result than the conventional Zn sources and indirectly prevents environmental contamination also. The toxicological studies provide mixed results in animal models. Studies been undertaken in diversified animal species and encouraging effects have been reported with nZn supplementation. However, there is a need to optimize the dose and duration of ZnO NP supplementation for human and livestock, depending on its biological effects. Actual bioavailability of ZnO NP in livestock is still to be worked out. In this review we have attempted to summarize, conclude the beneficial effects of nZnO and its possible usage as mineral supplement to different categories of human and livestock.