Involvement of Zn Depletion in Cd-Induced Toxicity on Prenatal Bone Formation in Rat

This experiment was conducted to evaluate the effects of chromium methionine with/without zinc sulfate or zinc amino acid complex on the growth performance, carcass traits, meat quality, serum parameters, endocrine parameters, and antioxidant status of growing-finishing pigs. A total of 180 (32.0 ± 1.7 kg body weight, BW) crossbred pigs (Duroc × Landrace × Yorkshire) were used in a completely randomized design with three dietary treatments and 10 replicates per treatment (five pens of barrows and five pens of gilts with six pigs per replicate). Three treatments were corn-soybean meal-based diets supplemented with 100 mg Zn/kg from zinc sulfate (ZnSO₄), 100 mg Zn/kg from ZnSO₄ + 0.2 mg Cr/kg from chromium methionine complex (CrMet), or 50 mg Zn/kg from ZnSO₄ + 50 mg Zn/kg from zinc amino acid complex (ZnAA) + 0.2 mg Cr/kg from CrMet, respectively. The experiment lasted 105 days, of which was divided into three stages including phase 1 (30 to 50 kg BW), phase 2 (50 to 80 kg BW), and phase 3 (80 to 110 kg BW). Results showed that supplementation with CrMet and ZnAA improved (P < 0.05) the feed conversion of the pigs in phase 2, phase 3, and the overall experiment. Hot carcass weight, dressing percentage, and a longissimus dorsi muscle area were increased (P < 0.05) in pigs fed with diets supplemented with both CrMet and ZnAA compared with pigs fed with diets containing only ZnSO₄ (P < 0.05). There was also an increase (P < 0.01) pH_24 h in the longissimus dorsi muscle in pigs fed with diets supplemented with CrMet and ZnAA. The concentration of serum glucose in pigs fed with diets containing CrMet and ZnAA was decreased (P < 0.05) compared with that in pigs fed with the diet containing ZnSO₄. Supplementation with CrMet and ZnAA increased (P < 0.05) the circulating levels of insulin and decreased (P < 0.05) cortisol. There was an increase (P < 0.05) in total serum antioxidant capacity and Cu/Zn superoxide dismutase activity as well as a decrease (P < 0.05) in serum malondialdehyde concentrations in pigs fed with diets supplemented with CrMet and ZnAA compared with pigs fed with the diet supplemented only with ZnSO₄. In conclusion, supplementation of CrMet only or CrMet together with ZnAA improved feed conversion, carcass traits, and meat quality in the growing-finishing pigs.     

Interaction of dietary zinc and growth implants on weight gain,carcass traits and zinc in tissues of growing beef steers and heifers

In two separate studies, 60 beef heifers (379 kg BW) and 60 beef steers (348 kg BW) were randomly assigned to six treatments in 2×3 factorial arrangements. The treatments were with or without Synovex^® implants combined with either a control diet or diets supplemented with 200 ppm Zn from ZnSO₄ or zinc methionine (Zn-Met). Near the mid-point of the feeding periods, cattle were vaccinated with a modified live virus and subsequent titers and concentrations of immunoglobulin G (IgG) were measured. Liver and blood samples were obtained 1 week prior to the start of the experiments and at intervals during the experiments. In experiment 1, average daily gains of beef heifers were (P<0.05) affected by the interaction of implant and source of dietary Zn. Compared to control and ZnSO₄ treatments, supplementation with Zn-Met increased (P<0.05) the concentration of Zn in serum. Antibody titers and concentrations of IgG in serum were highest (P<0.05) in heifers fed ZnSO₄ compared to heifers fed the control or Zn-Met supplemented diets. The Synovex-H^® implant reduced the concentrations of Zn and Cu in liver. In experiment 2, Synovex-S^® implants improved (P<0.05) weight gains of steers supplemented with 200 ppm dietary Zn from ZnSO₄ compared to non-implanted steers. However, the implant had no effect when Zn-Met was the dietary Zn source. The implant increased (P<0.05) concentrations of Zn in liver of steers supplemented with 200 ppm dietary Zn and reduced Zn in liver of steers fed the control diet. Implanted steers had higher (P<0.05) Cu status and IgG concentrations in serum than non-implanted steers. Steers supplemented with either ZnSO₄ or Zn-Met had greater (P<0.05) concentrations of Zn in liver and plasma than steers fed the control diet. These results indicate both the level and source of Zn supplementation in diets of feedlot cattle affect their response to growth implants.     

Equivalent uptake of organic and inorganic zinc by monkey kidney fibroblasts, human intestinal epithelial cells, or perfused mouse intestine

Zinc (Zn) is recognized as an essential nutrient, and is added as a supplement to animal and human diets. There are claims that zinc methionine (ZnMet) forms a stable complex that is preferentially transported into tissues, and this has contributed to uncertainty about conflicting reports on the bioavailability of various Zn compounds. This study evaluated the cellular and intestinal uptake of inorganic and organic forms of Zn. Steady-state uptake of⁶⁵Zn by human intestine epithelial cells, and monkey kidney fibroblasts was not significantly different with zinc chloride (ZnCl₂), ZnMet, or zinc propionate (ZnProp) (P > 0.05). Uptake of⁶⁵Zn from zinc chelated with EDTA was significantly lower (P < 0.01). In live mice,⁶⁵Zn uptake by perfused intestine and deposition in intestine and liver showed no significant difference between ZnCl₂ and ZnMet. Equimolar [⁶⁵Zn]methionine and zinc[³⁵S]methionine were prepared according to a patented method that yields “ complexed” Zn. Cellular uptake of the radiolabeled methionine was <0.1% of the radiolabeled Zn from these complexes, indicating separate uptake of the Zn and methionine. Gel filtration did not distinguish between⁶⁵Zn in ZnCl₂, ZnProp, or reagent ZnMet, though feed-grade ZnMet containing >10% protein did give a higher-mol-wt form of⁶⁵Zn. Results of this study show equivalent uptake of Zn from inorganic and organic compounds, and support recent feed trials on Zn bioavailability.     

Effect of zinc on the toxicity of the mycotoxin sporidesmin to the rat

The toxicity of sporidesmin to rats fed diets containing either 4 ppm or 200 ppm Zn was determined. The high zinc diet doubled the LD₅₀ level for sporidesmin given as a single dose, but the LD₅₀ dose for rats on a zinc deficient diet was not significantly different from that for rats on a diet containing zinc at levels sufficient for normal growth. Subsequent trials demonstrated that large doses of ZnSO₄ given orally protected rats from sporidesmin poisoning. The protection was short lived as zinc needed to be given at or soon after sporidesmin challenge.     

Relative bioavailabilities of organic zinc sources with different chelation strengths for broilers fed diets with low or high phytate content

A six-day experiment was conducted to estimate the relative bioavailability values (RBV) of zinc (Zn) in three organic sources (oZn) with different chelation strengths compared to inorganic ZnSO₄ (iZn) for broilers fed a low or high phytate diet. A total of 1080, one-d-old male broiler chicks were randomly assigned to one of 18 dietary treatments (six replicates cages of ten chicks per cage) in a completely randomized design involving a 2 × 2 × 4 factorial arrangement with two levels of added phytate (0 or 10 g phytate as sodium phytate/kg), two levels of added Zn (30 or 60 mg/kg) and four Zn sources (iZn and three oZn sources) plus one low and one high phytate control treatments without Zn addition. The three oZn sources consisted of (1) Zn amino acid with weak chelation strength (ZnAA-L, formation quotient Q_f = 6.6, containing 119 g Zn/kg), (2) Zn proteinate with moderate chelation strength (ZnPRO-M, Q_f = 30.7, containing 133 g Zn/kg) or (3) Zn proteinate with strong chelation strength (ZnPRO-H, Q_f = 944.0, containing 186 g Zn/kg). Chicks were harvested at 6 days of age and pancreas metallothionein (MT) mRNA expression was used to estimate Zn RBV. Pancreas MT mRNA expression increased (P<0.01) as dietary Zn level increased. Chicks fed high phytate diets had lower (P<0.05) MT mRNA expression than chicks fed low phytate diets. Based on multiple linear regression slope ratios with ZnSO₄ set at 1.00, the RBV of ZnAA-L, ZnPRO-M and ZnPRO-H were 1.01, 1.28 and 0.70, respectively, for low phytate diets, and 1.05, 1.39 and 0.92, respectively, for high phytate diets. The slope for the oZn source with moderate chelation strength differed (P<0.05) from iZn and the other two oZn sources. The RBV of ZnAA-L, ZnPRO-M and ZnPRO-H under the high phytate diet increased by 0.04, 0.11 and 0.22, respectively, compared to those under the low phytate diet. Results indicate that the oZn sources with moderate or strong chelation strength offer partial or complete resistance to interference from high dietary phytate during digestion; and the oZn with moderate chelation strength had a greater RBV with both low and high phytate diets than iZn or oZn sources with weak or strong chelation strength.     

黄颡鱼饲料中添加谷胱甘肽降低藻毒素毒性作用的研究

通过60d的生长实验研究饲料中不同含量的谷胱甘肽(GSH)对黄颡鱼(Pelteobagrus fulvidraco Richardson)摄食含蓝藻粉饲料后的毒性保护作用。共配制6种近似等氮等能(粗蛋白45%,总能19.5kJ/g)的实验饲料。以不添加蓝藻粉、不添加GSH的饲料组作为正对照,其他5种饲料均添加7.5%的藻粉,微囊藻毒素(Microc ystins,MCs)含量约为58μg/g,GSH添加量分别为:0(负对照)、200、500、800和1400mg/kg。实验结果表明,第1至第30天时,负对照组与正对照组实验鱼的摄食率无显著性差异(P>0.05)。第31至第60天时,负对照组实验鱼的摄食率显著高于正对照和其他GSH添加组(P0.05),但各GSH添加组肾脏中GSH显著低于正对照而高于负对照(P<0.05)。200、500和800mg/kg GSH添加组肝脏和肌肉中丙二醛(MDA)含量显著低于负对照(P<0.05)。在整个实验期间,随着饲料中GSH含量的增加,肝脏、肾脏、全肠和肌肉中微囊藻毒素含量先显著下降,当GSH添加量为500和800mg/kg时达到稳定,直至GSH添加量为1400mg/kg时显著上升。根据对黄颡鱼增重,肝脏和肌肉中MDA的含量以及组织中毒素的分析,在饲料中添加500-800mg/kg GSH可以有效缓解黄颡鱼饲料中微囊藻毒素的毒性。       

Molecular characterization of ten zinc (Zn) transporter genes and their regulation to Zn metabolism in freshwater teleost yellow catfish Pelteobagrus fulvidraco

BackgroundZn is an essential trace element for vertebrates, and Zn uptake and transport is related with the ZIP family of Zn transporters. Meantime, Zn also influenced the expression of ZIP family members.MethodsWe cloned and characterized the full-length cDNA sequences of ten Zn transport-relevant genes (ZIP1, ZIP3, ZIP6, ZIP7, ZIP8, ZIP9, ZIP10, ZIP11, ZIP13 and ZIP14) from yellow catfish Pelteobagrus fulvidraco, investigated their mRNA tissue expression. These ZIP mRNA expression was also assessed in the primary hepatocytes and intestinal epithelial cells of yellow catfish in response to three Zn levels (0, 30 μM and 60 μM, respectively).ResultsAll these genes shared the similar domains with the corresponding members in mammals. The mRNA expression of the ten ZIP genes was detected in nine-tested tissues, but variable among these tissues. Flow cytometry analysis and confocal microscopy observation indicated that intracellular free Zn²⁺ concentration in hepatocytes and intestinal epithelial cells increased with increasing Zn incubation concentration at both 24 h and 48 h. Zn incubation differentially influenced mRNA levels of ZIP transporters in the hepatocytes and intestinal epithelial cells, in a time- and cells-dependent manners. In the hepatocytes, at 24 h, compared to the control, Zn addition down-regulated mRNA levels of ZIP1, ZIP3, ZIP6, ZIP7, ZIP8, ZIP9, ZIP11 and ZIP14; however, ZIP10 mRNA levels were lower in 60 μM Zn group than those in the control and 30 μM Zn group. At 48 h, mRNA levels of ZIP1, ZIP6, ZIP7, ZIP9, ZIP10 and ZIP14 declined with increasing Zn incubation concentrations; ZIP3 mRNA levels were the lowest in 60 μM Zn group and showed no significant differences between the control and 30 μM Zn group. In the intestinal epithelial cells, at 24 h, Zn addition down-regulated mRNA levels of ZIP1, ZIP6, ZIP7, ZIP8, ZIP9, ZIP10, ZIP11, ZIP13 and ZIP14; ZIP3 mRNA levels were lower in 60 μM Zn group than those in the control and 30 μM Zn group. At 48 h, Zn addition up-regulated mRNA levels of ZIP6 and ZIP9, but down-regulated mRNA levels of ZIP8, ZIP10 and ZIP13. ZIP7, ZIP11 and ZIP14 mRNA abundances were the lowest in 60 μM Zn group and showed no significant differences between the control and 30 μM Zn group.ConclusionFor the first time, our study characterized ten ZIP family members in yellow catfish, explored their mRNA tissue expression. Their regulation to Zn addition were also investigated in the hepatocytes and intestinal epithelial cells of yellow catfish. Our study revealed the mechanism of cells exposed to Zn addition and provided novel insights for the regulatory mechanism of Zn homeostasis.     

Study on Zn Relative Concentration and State in Sheep Duodenum by XAFS

Synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy is not widely used in animal science. The objective of this study was to employ the XAFS technique to determine changes in zinc absorption and concentrations in the sheep interstinal sac using different zinc sources. Forty-eight sheep were slaughtered and their duodena were dissected. The duodena were randomly assigned to six zinc sources (ZnO, ZnSO₄, ZnMet, ZnLys, ZnSO₄ + methionine, ZnSO₄ + lysine). Ten centimeters of duodenal sac midpiece was incubated for 40 min in vitro using the everted intestinal sac technique in culture medium containing zinc from different sources. The amount of zinc present was normalized to 4 mg. XAFS was used to analyze the relative concentration and oxidation state of zinc, and atomic absorption spectrometry (AAS) was used to verify zinc concentration. The results showed that, for increasing zinc concentrations, organic zinc was a better source than inorganic zinc. In addition, the zinc concentration achieved using ZnMet was higher than that for ZnO and ZnSO₄ (P < 0.05) as measured by atomic absorption spectroscopy. The results using XAFS were consistent with that of AAS. The states of organic zinc and inorganic zinc were identical after being incubated for 40 min. As observed in these experiments, organic zinc was more easily absorbed than inorganic zinc. Our data demonstrate that organic zinc was dissociated into ions and then absorbed as inorganic zinc. In our experiments, we are the first investigators to use XAFS spectroscopy to determine zinc absorption in the sheep duodenal wall. We observed reduced absorption of inorganic zinc in the presence of methionine or lysine. Taken together, we postulate that the optimal molar ratio of inorganic zinc and ligand requires further study.     

Effects of Zinc Glycinate on Productive and Reproductive Performance,Zinc Concentration and Antioxidant Status in Broiler Breeders

An experiment was conducted to investigate the effects of zinc glycinate (Zn-Gly) supplementation as an alternative for zinc sulphate (ZnSO₄) on productive and reproductive performance, zinc (Zn) concentration and antioxidant status in broiler breeders. Six hundred 39-week-old Lingnan Yellow broiler breeders were randomly assigned to 6 groups consisting of 4 replicates with 25 birds each. Breeders were fed a basal diet (control group, 24 mg Zn/kg diet), basal diet supplemented with 80 mg Zn/kg diet from ZnSO₄ or basal diet supplemented with 20, 40, 60 and 80 mg Zn/kg diet from Zn-Gly. The experiment lasted for 8 weeks after a 4-week pre-test with the basal diet, respectively. Results showed that Zn supplementation, regardless of sources, improved (P?<?0.05) the feed conversion ratio (kilogram of feed/kilogram of egg) and decreased broken egg rate, and elevated (P?<?0.05) the qualified chick rate. Compared with the ZnSO₄ group, the 80 mg Zn/kg Zn-Gly group significantly increased (P?<?0.05) average egg weight, fertility, hatchability and qualified chick rate, whereas it decreased (P?<?0.05) broken egg rate. The Zn concentrations in liver and muscle were significantly higher (P?<?0.05) in 80 mg Zn/kg Zn-Gly group than that in ZnSO₄ group. Compared with ZnSO₄ group, 80 mg Zn/kg Zn-Gly group significantly elevated (P?<?0.05) the mRNA abundances of metallothionein (MT) and copper-zinc superoxide (Cu-Zn SOD), as well as the Cu-Zn SOD activity and MT concentration in liver. Moreover, the 80 mg Zn/kg Zn-Gly group had higher (P?<?0.05) serum T-SOD and Cu-Zn SOD activities than that in the ZnSO₄ group. This study indicated that supplementation of Zn in basal diet improved productive and reproductive performance, Zn concentration and antioxidant status in broiler breeders, and the 80 mg Zn/kg from Zn-Gly was the optimum choice for broiler breeders compared with other levels of Zn from Zn-Gly and 80 mg/kg Zn from ZnSO₄.     

Interactive effects of zinc and nickel on the glutathione system state in <Emphasis Type="Italic">Mimulus guttatus</Emphasis> plants

To determine whether the enhanced stress tolerance of ZnSO₄ with NiSO₄-treated Mimulus guttatus Fischer ex DC. plants was associated with the glutathione (GR-GSH) system, we investigated the changes in glutathione redox state (reduced (GSH), oxidized (GSSG) forms, total reduced (GSHt) glutathione, and GSH/GSSG ratio) and in the enzymatic activities of glutathione reductase (GR) and peroxidatic glutathione S-transferases (GST). The 6-week-old plants were grown in water culture during 4 weeks on a modified Rorison’s medium with ZnSO₄ (50, 100, and 200 μM) and NiSO₄ (20 and 80 μM) in a condition of separate or simultaneous supply of the components. Dry biomass accumulations of roots and shoots were not influenced by the examined treatments. The positive correlations between the total external concentrations of ZnSO₄ and NiSO₄ and the total Zn and Ni contents in roots and leaves were found. It was determined that the MDA content was higher in the ZnSO₄-treated plants than in the NiSO₄-treated ones. The supplementation of the ZnSO₄-treated plants with varied concentrations of NiSO₄ decreased the Zn-induced increase in the MDA levels. The inverse proportionality between the MDA and pigment levels in leaves was found. The Zn-Ni interactions were shown to induce the decreases in the GR activity, the total peroxidatic GST activity, and the GSH/GSSG ratio in roots. However, in leaves, the GR activity and the GSH/GSSG ratio were significantly increased and the total peroxidatic GST activity was decreased. The supplementation of the ZnSO₄-treated plants with varied concentrations of NiSO₄ restored the Zn-induced reduction in the GSHt levels in roots and decreased the Zn-induced increase in the GSSG levels in leaves, which resulted in more reduced state of the intracellular environment. It was likely to cause a decrease of the MDA level. Thus, our studies on the Zn?Ni interactions identified the antagonizing role of Ni in Zn toxicity by the GR-GSH system.     

棉籽粕和菜籽粕替代部分鱼粉对黄颡鱼肉质及肌肉发育相关基因表达的影响

文章旨在研究菜籽粕与棉籽粕复合替代饲料鱼粉对黄颡鱼(Pelteobagrus fulvidraco)肌肉品质及肌纤维发育相关基因表达的影响。实验设计了5组等氮等能的饲料,以含鱼粉25%的处理组为对照饲料(FM),以菜籽粕与棉籽粕3﹕2混合后分别替代其中的10%、20%、30%和40%鱼粉,设置了RM10、RM20、RM30和RM40四个试验组。使用初始体质量为(2.38±0.10) g的黄颡鱼幼鱼,分别用上述5种饲料饲喂10周。试验表明,与对照组相比,菜粕棉粕混合替代水平达到20%及以上时黄颡鱼肌肉中的粗蛋白与粗脂肪显著降低,而水分和灰分则无显著差异;肌肉中的羟脯氨酸含量呈现下降的趋势;肌纤维中直径≥50μm的纤维数量随着替代水平达到20%后不断减小,而≤20μm的纤维数量则呈现上升趋势;植物蛋白源的替代也会对黄颡鱼的肌肉质构产生一定的影响。此外,肌肉纤维发育相关基因myod、myog和mrf4的mRNA水平随着替代水平上升而逐渐升高,而myf5与mstn的基因表达在各组间无显著差异。TOR通路相关基因中的akt、tor和s6k1等基因随着替代水平升高而下降, 4e-bp1则随着替代水...     

An Optimal Dietary Zinc Level of Brown-Egg Laying Hens Fed a Corn–Soybean Meal Diet

An experiment was conducted to estimate the optimal dietary zinc (Zn) level of brown-egg laying hens fed a corn–soybean meal diet from 20 to 40 weeks of age. A total of 120 20-week-old Beijing Red commercial laying hens were randomly allotted by bodyweight to one of five treatments with six replicates of four birds each in a completely randomized design, and fed a Zn-unsupplemented corn–soybean meal basal diet containing 27.95 mg Zn/kg by analysis and the basal diets supplemented with 30, 60, 90, or 120 mg Zn/kg as Zn sulfate (reagent grade ZnSO₄·7H₂O) for a duration of 20 weeks. Laying performance, egg quality, tissue Zn concentrations, and activities of serum alkaline phosphatase (AKP), and liver copper-Zn superoxide dismutase (CuZnSOD) were measured. Regression analyses were performed to estimate an optimal dietary Zn level whenever a significant quadratic response (P < 0.05) was observed. Tibia Zn concentration (P = 0.002) and serum AKP activity (P = 0.010) showed significant quadratic responses to dietary supplemental Zn levels. The estimates of dietary Zn requirements for brown-egg laying hens from 20 to 40 weeks of age were 71.95 and 64.63 mg/kg for tibia Zn concentration and serum AKP activity, respectively. The results from this study indicate that the tibia Zn might be a more suitable and reliable parameter for Zn requirement estimation, and the optimal dietary Zn level would be about 72 mg/kg for brown-egg laying hens fed a corn–soybean meal diet from 20 to 40 weeks of age.     

Characterization and tissue expression of twelve selenoproteins in yellow catfish Pelteobagrus fulvidraco fed diets varying in oxidized fish oil and selenium levels

BackgroundSelenium (Se) functions through selenoproteins and is essential to growth and metabolism of vertebrates. The present study was conducted to identify twelve selenoproteins genes (selenoe, selenof, selenoh, selneoi, selenom, selenok, selneon, selenoo, selenot, selenos, selenou and msrb1) from yellow catfish. Their mRNA expression patterns, as well as their response to dietary oxidized fish oils and Se addition were explored.MethodsWe use 3′and 5′ RACE PCR to clone full-length cDNA sequence of twelve selenoprotein genes from yellow catfish. Their mRNA expression patterns were assessed via quantitative real-time PCR. Yellow catfish were fed diet adequate Se+ fresh fish oil, adequate Se+ oxidized fish oil, high Se+ fresh fish oil and high Se+ oxidized fish oil, respectively, for 10 weeks. Their kidney, heart, brain and testis were used to assess the mRNA expression of twelve selenoprotein.ResultsTwelve selenoprotein genes had similar domains with mammals and the other fish. Their mRNAs were expressed widely in eleven tissues but varied with the tissues. Dietary oxidized fish oils and Se addition influenced their mRNA abundances of twelve selenoproteins in a tissue-dependent manner.ConclusionOur study demonstrated the characterization and expression of twelve selenoproteins, and elucidated their responses in yellow catfish fed diets varying in oxidized fish oils and Se addition, which increased our knowledge into the biological function and regulatory mechanism of Se and selenoproteins in fish.     

Effects of zinc source and dietary concentration on serum zinc concentrations,growth performance,wool and reproductive characteristics in developing rams

Dietary Zn has significant impacts on the growth and development of breeding rams. The objectives of this study were to evaluate the effects of dietary Zn source and concentration on serum Zn concentration, growth performance, wool traits and reproductive performance in rams. Forty-four Targhee rams (14 months; 68 ± 18 kg BW) were used in an 84-day completely randomized design and were fed one of three pelleted dietary treatments: (1) a control without fortified Zn (CON; n = 15; ~1 × NRC); (2) a diet fortified with a Zn amino acid complex (ZnAA; n = 14; ~2 × NRC) and (3) a diet fortified with ZnSO₄ (ZnSO₄; n = 15; ~2 × NRC). Growth and wool characteristics measured throughout the course of the study were BW, average daily gain (ADG), dry matter intake (DMI), feed efficiency (G : F), longissimus dorsi muscle depth (LMD), back fat (BF), wool staple length (SL) and average fibre diameter (AFD). Blood was collected from each ram at four time periods to quantify serum Zn and testosterone concentrations. Semen was collected 1 to 2 days after the trial was completed. There were no differences in BW (P = 0.45), DMI (P = 0.18), LMD (P = 0.48), BF (P = 0.47) and AFD (P = 0.9) among treatment groups. ZnSO₄ had greater (P ≤ 0.03) serum Zn concentrations compared with ZnAA and CON treatments. Rams consuming ZnAA had greater (P ≤ 0.03) ADG than ZnSO₄ and CON. There tended to be differences among groups for G : F (P = 0.06), with ZnAA being numerically greater than ZnSO₄ and CON. Wool staple length regrowth was greater (P < 0.001) in ZnSO₄ and tended to be longer (P = 0.06) in ZnAA treatment group compared with CON. No differences were observed among treatments in scrotal circumference, testosterone, spermatozoa concentration within ram semen, % motility, % live sperm and % sperm abnormalities (P ≥ 0.23). Results indicated beneficial effects of feeding increased Zn concentrations to developing Targhee rams, although Zn source elicited differential responses in performance characteristics measured.     

Growth and survival of river catfish Mystus nemurus (Cuvier & Valenciennes) larvae fed isocaloric diets with different protein levels during weaning

The growth of river catfish Mystus nemurus (Cuvier & Valenciennes) larvae fed four isocaloric diets (4200 kcal kg^?1) with different protein levels during weaning was determined. Diets containing 45, 50, 55, and 60% protein were formulated by linear programming using amino acid profiles based on that of 2‐day‐old river catfish larvae. Artificial diets were fed to the larvae beginning at day 5 after being initially fed Artemia nauplii for 4 days. The larvae thrived solely on artificial diets from day 8 to day 16. On the other hand, the control larvae were fed Artemia nauplii from day 1 to day 16. Results of the feeding trial showed that growth and survival of M. nemurus larvae given the diet containing 60% protein were high and comparable to those of the larvae given only live food (control). Larvae fed the 55% protein diet had significantly lower growth and survival than the larvae on the control and 60% diets but significantly higher growth and survival rates than did larvae fed with 45 and 50% protein diets. Carcass moisture and total lipids after 16 days of feeding did not differ significantly (P > 0.05), but body protein increased with increasing dietary protein. Body protein of the control larvae was similar to that of larvae given the 60% protein diet.     

Biofortification and Bioavailability of Rice Grain Zinc as Affected by Different Forms of Foliar Zinc Fertilization

Background

Zinc (Zn) biofortification through foliar Zn application is an attractive strategy to reduce human Zn deficiency. However, little is known about the biofortification efficiency and bioavailability of rice grain from different forms of foliar Zn fertilizers.

Methodology/Principal Findings

Four different Zn forms were applied as a foliar treatment among three rice cultivars under field trial. Zinc bioavailability was assessed by in vitro digestion/Caco-2 cell model. Foliar Zn fertilization was an effective agronomic practice to promote grain Zn concentration and Zn bioavailability among three rice cultivars, especially, in case of Zn-amino acid and ZnSO₄. On average, Zn-amino acid and ZnSO₄ increased Zn concentration in polished rice up to 24.04% and 22.47%, respectively. On average, Zn-amino acid and ZnSO₄ increased Zn bioavailability in polished rice up to 68.37% and 64.43%, respectively. The effectiveness of foliar applied Zn-amino acid and ZnSO₄ were higher than Zn-EDTA and Zn-Citrate on improvement of Zn concentration, and reduction of phytic acid, as a results higher accumulation of bioavailable Zn in polished rice. Moreover, foliar Zn application could maintain grain yield, the protein and minerals (Fe and Ca) quality of the polished rice.

Conclusions

Foliar application of Zn in rice offers a practical and useful approach to improve bioavailable Zn in polished rice. According to current study, Zn-amino acid and ZnSO₄ are recommended as excellent foliar Zn forms to ongoing agronomic biofortification.     

Effect of organic zinc supplementation on growth, nutrient utilization and mineral profile in lambs

To study the efficacy of organic zinc (Zn) supplementation on growth, nutrient utilization and mineral profile as compared to inorganic source [zinc sulphate (ZnSO₄)], 18 Muzaffarnagari male lambs of 11.30 ± 0.45 kg mean body weight (4–5 months of age) were divided into three groups of six animals in each in a randomized block design. Lambs in the control group were fed a standard total mixed ration (TMR) consisted of 60 kg/100 kg of concentrate mixture (CM) and 40 kg/100 kg of wheat straw. CM was consisted of 300 g/kg crushed maize grain, 270 g/kg soybean meal, 400 g/kg wheat bran, 20 g/kg mineral mixture (without Zn) and 10 g/kg common salt. Animals in the experimental groups were additionally supplemented with 20 mg Zn/kg of diet either through inorganic (ZnSO₄) or organic [Zn-methionine AA complex (Zn-meth)] sources. Experimental feeding was done for a period of 150 days including a 6 days metabolism trial. The intake of dry matter (DM), organic matter (OM), crude protein (CP), digestible CP and total digestible nutrients and digestibility of DM, OM, CP, ether extract, neutral detergent fibre and hemicellulose were comparable (P>0.05) among the three groups. However, digestibility of cellulose and acid detergent fibre was significantly (P<0.05) higher in Zn-meth group as compared to control group. Though the balance of calcium was adversely affected (P<0.01) in both the Zn supplemented groups, but it was significantly higher in Zn-meth group compared to ZnSO₄ group. While apparent absorption and retention of nitrogen, phosphorus, copper, iron and manganese were similar (P>0.05) among different groups, retention of Zn (P<0.05) as well as its concentration in the serum (P<0.01) were highest in Zn-meth group, followed by ZnSO₄ group and lowest in the control group, suggesting higher bioavailability of Zn from Zn-meth as compared to ZnSO₄. Average daily gain of the lambs and feed conversion efficiency were also significantly (P<0.05) higher in Zn-meth group as compared to control and ZnSO₄ groups, suggesting a positive role of organic zinc supplementation on the performance of lambs.     

蛋氨酸锌螯合物中的锌在山羊体内代谢规律的研究

将１０头体重为９ｋｇ左右的健康浏阳黑公山羊分成两组,在代谢笼内个体饲喂,分别喂以含６５Ｚｎ蛋氨酸Ｚｎ（６５ＺｎＭｅｔ）和６５Ｚｎ硫酸锌（６５ＺｎＳＯ４）的饲粮,以比较研究蛋氨酸锌螯合物中的Ｚｎ在山羊体内的代谢规律．结果表明,６５ＺｎＭｅｔ组在粪中排出６５Ｚｎ的浓度低于６５ＺｎＳＯ４组,在饲喂６５ＺｎＭｅｔ螯合物３ｄ期间Ｚｎ的表观吸收率为４９．１２％,显著地（α＜０．０５）高于６５ＺｎＳＯ４（３８．９１％）组,５２ｈ达到排泄高峰．６５ＺｎＭｅｔ组与６５ＺｎＳＯ４组６５Ｚｎ在体内的存留率分别为４０．３８％与２９．５２％,差异显著（α＜０．０５）;停止饲喂６５Ｚｎ后的第３ｄ,两组体内存留趋于平衡,６５ＺｎＭｅｔ组与６５ＺｎＳＯ４分别为４．８８与４．７４ｍｇ;在组织器官中Ｚｎ的分布规律两组几乎相同,单位含量均以肝、脾、胰含量高,骨、蹄含量低     

Optimized production of Pichia guilliermondii biomass with zinc accumulation by fermentation

Zinc is an essential nutrient that plays an important role in several biological processes of living organisms. When bound to an organic substrate, Zn is more efficiently absorbed by organisms, has a high biological activity and a low toxicity. Due to its ability to incorporate metals, yeast biomass has been used frequently as a delivery vehicle for many mineral supplements. This study describes the screening of strains of yeast for production of biomass enriched with Zn by submerged fermentation. Five strains of yeasts, belonging to the genera Saccharomyces, Kluyveromyces and Pichia, were evaluated. The highest Zn concentration was 6820 mg/kg of dry weight biomass, using Pichia guilliermondii Wickerham LPB 063 after 120 h of cultivation in a medium with 0.5 g/L ZnSO₄. Process conditions were optimized using statistical experimental design methodology. Four parameters were identified in the 2⁸⁻⁴ fractional factorial design as having a significant effect on Zn accumulation: ZnSO₄ and Fe₂(SO₄)₃ concentrations, time of addition of the ZnSO₄ solution and concentration of soybean molasses. In the 3² experimental design, the influence of ZnSO₄ and Fe₂(SO₄)₃ concentrations were studied more closely. The highest Zn concentration (75,090 mg/kg dry weight) in the biomass was reached using the conditions: ZnSO₄, 10.0 g/L; Fe₂(SO₄)₃, 0.1 g/L in Erlenmeyer flasks. A batch liquid fermentation was carried out in a 2 L bioreactor for production of P. guilliermondii Wickerham LPB 063 containing organically bound Zn. The concentration of organically bound Zn after 144 h of fermentation was of 96,030 mg/kg, with a biomass production of 30 g/L. The maximum specific growth rate obtained (μ_max) was 0.0077/h, while the maximum productivity of biomass was at 0.1511 g/L/h.     

Characterization and expression analysis of seven selenoprotein genes in yellow catfish Pelteobagrus fulvidraco to dietary selenium levels

BackgroundSelenium (Se) appears in the selenoproteins in the form of selenocysteine (Sec) and is important for the growth and development of vertebrates. The present study characterized seven selenoproteins, consisting of the GPX1, GPX3, GPX4, SELENOW, SELENOP, TXNRD2 and TXNRD3 cDNAs in various tissues of yellow catfish, explored their regulation to dietary Se addition.Methods3′ and 5′ RACE PCR were used to clone full-length cDNA sequences of seven selenoprotein genes (GPX1, GPX3, GPX4, SELENOW, SELENOP, TXNRD2 and TXNRD3). Their molecular characterizations were analyzed, including conservative motifs and the SECIS elements. The phylogenetic trees were generated through neighbor-joining (NJ) method with MEGA 6.0 with 1000 bootstrap replications. Quantitative real-time PCR was used to explore their mRNA tissue distribution in the heart, anterior intestine, dorsal muscle, head kidney, gill, liver, brain, spleen and mesenteric fat. Yellow catfish (mixed sex) were fed diets with dietary Se contents at 0.03 (low Se), 0.25 (adequate Se) and 6.39 (high Se) mg Se/kg, respectively, for 12 weeks, and their spleen, kidney, testis and brain were used for the determination of the mRNA levels of the seven selenoproteins.ResultsThe seven selenoproteins had similar domains to their corresponding members of other vertebrates. They were widely expressed in nine tissues, including heart, liver, brain, spleen, head kidney, dorsal muscle, mesenteric fat, anterior intestine and gill, but showed tissue-dependent expression patterns. Dietary Se addition affected the expression of the seven genes in spleen, kidney, testis and brain tissues of yellow catfish.ConclusionTaken together, our study demonstrated the characterization, expression and regulation of seven selenoproteins, which increased our understanding of the biological functions of Se and selenoproteins in fish.