Zinc glycine chelate absorption characteristics in Sprague Dawley rat

This study was conducted to investigate absorption characteristics of zinc glycine chelate (Zn–Gly) by evaluating tissues zinc status and the expression of zinc transporters in rats. A total of 24 male rats were randomly allocated to three treatments and administered either saline or 35 mg Zn/kg body weight from zinc sulphate (ZnSO₄) or Zn–Gly by feeding tube separately. Four rats per group were slaughtered and tissues were collected at 2 and 6 h after gavage respectively. Our data showed that Zn–Gly did more effectively in increasing (p < 0.05) serum zinc levels, and the activities of serum and liver alkaline phosphatase (ALP) and liver Cu/Zn superoxide dismutase (Cu/Zn SOD) at 2 and 6 h. By 2 h after the zinc load, the mRNA and protein abundance of intestinal metallothionein1 (MT1) and zinc transporter SLC30A1 (ZnT1) were higher (p < 0.05), and zinc transporter SLC39A4 (Zip4) lower (p < 0.05) in ZnSO₄ compared to other groups. Zinc transporter SLC39A5 (Zip5) mRNA expression was not zinc responsive, but Zip5 protein abundance was remarkably (p < 0.05) increased in ZnSO₄ 2 h later. Overall, our results indicated that in short‐term periods, Zn–Gly was more effective in improving body zinc status than ZnSO₄, and ZnSO₄ did more efficiently on the regulation of zinc transporters in small intestine.     

Changes in diarrhea,nutrients apparent digestibility,digestive enzyme activities of weaned piglets in response to chitosan‐zinc chelate

A total of 120 weanling barrows weighing 6.11 ± 0.20 kg were randomly allotted to four treatments with three replications (i.e. pen) of ten piglets per replicate. Pigs were received corn‐soybean basal diet (control) or the same basal diet supplemented with the following sources of zinc: (i) 100 mg/kg of Zn as ZnSO₄; (ii) 100 mg/kg of Zn as chitosan‐Zn chelate (CS‐Zn); and (iii) 100 mg/kg of Zn as ZnSO₄ mixed with chitosan (CS + ZnSO₄). The results showed that CS‐Zn could highly improve average daily gain and average daily feed intake than those of ZnSO₄ or CS+ ZnSO₄ (P < 0.05). The pigs fed dietary CS‐Zn had lower diarrhea incidence and higher apparent digestibility of crude protein than those of the pigs fed dietary ZnSO₄ (P < 0.05). The protease activities in duodenal content of the pigs receiving CS‐Zn diets was higher than that of the pigs fed dietary ZnSO₄ or CS + ZnSO₄ (P < 0.05). The amylase activity in duodenal content of the pigs fed dietary CS‐Zn was higher than that of the pigs receiving ZnSO₄ diets or basal diets (P < 0.05). These results indicated that dietary CS‐Zn showed different bioactivities from ZnSO₄ or CS + ZnSO₄ in reducing the incidence of diarrhea, improving activities of digestive enzymes and growth performance of weaned pigs.     

Effects of dietary supplementation with tribasic zinc sulfate or zinc sulfate on growth performance,zinc content and expression of zinc transporters in young pigs

An experiment was conducted to compare the effects of zinc sulfate (ZS) and tribasic zinc sulfate (TBZ) as sources of supplemental zinc on growth performance, serum zinc (Zn) content and messenger RNA (mRNA) expression of Zn transporters (ZnT1/ZnT2/ZnT5/ZIP4/DMT1) of young growing pigs. A total of 96 Duroc × Landrace × Yorkshire pigs were randomly allotted to two treatments and were fed a basal diet supplemented with 100 mg/kg Zn from either ZS or TBZ for 28 days. Feed : gain ratio in pigs fed TBZ were lower (P < 0.05) than pigs fed ZS, and average daily weight gain tended to increase (0.05 ≤ P ≤ 0.10) in pigs fed TBZ. Compared with pigs fed ZS, pigs fed TBZ had a higher CuZn‐superoxide dismutase and Zn content in serum (P < 0.05) while they had a lower Zn content in feces (P < 0.05). In addition, ZIP4 mRNA expression of zinc transporter in either duodenum or jejunum of pigs fed TBZ were higher (P < 0.05) than pigs fed ZS. These results indicate that TBZ is more effective in serum Zn accumulation and intestinal Zn absorption, and might be a potential substitute for ZS in young growing pigs.     

Effects of zinc oxide nanoparticles on the egg quality,immune response,zinc retention,and blood parameters of laying hens in the late phase of production

The objective of this study was to evaluate the effects of dietary supplementation with zinc oxide nanoparticles (ZnO‐NPs) on the performance, egg quality, Zn retention, immunity responses, superoxide dismutase activity (SOD), egg malondialdehyde (MDA) content, and serum parameters in laying hens in the late phase of production. A total of 288 laying hens at 64 weeks of age were randomly assigned to 4 treatments with 6 replicates, and 12 birds within each group. Experimental diets included a corn‐soybean meal‐based diet (without Zn supplementation) and a basal diet supplemented with 80 mg/kg of Zn‐oxide, ZnO‐NPs, and Zn‐methionine. The results indicated that egg production and egg mass were significantly higher in the Zn‐methionine and ZnO‐NPs groups (p < .05). Also, eggshell thickness and shell strength increased in the ZnO‐NPs group as compared with the other groups (p < .05). Moreover, Zn supplementation decreased egg loss (p < .05). There were significant differences among treatments in Zn deposition in tibiotarsus, liver, pancreas, eggs, and excreta (p < .01). Antibody titre, heterophil (%(, and phytohemagglutinin (PHA) were significantly higher in birds fed with Zn‐supplemented diets (p < .05). In treatments supplemented with ZnO‐NPs and Zn‐methionine, the SOD activity in the liver, pancreas, and plasma was greater as compared with the other treatments (p < .05). The MDA content in eggs was significantly reduced in groups supplemented with Zn (p < .01). Moreover, dietary Zn supplementation significantly affected serum total protein, albumin, glucose, alkaline phosphatase activity, carbonic anhydrase activity, and Zn level (p < .05). In conclusion, this study demonstrated that dietary supplementation with ZnO‐NPs can improve the performance of laying hens. Therefore, ZnO‐NPs can enhance zinc absorption in the intestine of aged layers and can be a more suitable source of zinc than regular Zn‐oxide in diets.     

Effect of pectin oligosaccharides and zinc chelate on growth performance,zinc status,antioxidant ability,intestinal morphology and short‐chain fatty acids in broilers

A 42‐day trial was conducted to investigate the effect of pectin oligosaccharides (POS) and zinc chelate (Zn‐POS) on growth performance, antioxidant ability, zinc status, intestinal morphology and short‐chain fatty acids in broilers. A total of 324 1‐day‐old Arbor Acres broilers were randomly assigned to three treatments with six cages of 18 chicks. Treatments were: (a) Control, 80 mg/kg Zn from ZnSO₄; (b) POS, 80 mg/kg Zn from ZnSO₄ + 482 mg/kg POS (the same amount of POS as treatment 3); and (c) Zn‐POS, 80 mg/kg zinc from Zn‐POS. Compared to the Control, both POS and Zn‐POS supplementation increased average daily gain and reduced the mortality during day 22–42, and only Zn‐POS supplementation decreased the ratio of feed to gain during day 22–42 and 1–42. Moreover, both POS and Zn‐POS supplementation improved Zn status and gut function as evidenced by increased metallothionein concentrations in the pancreas, villus height in the duodenum and isobutyrate concentrations in the caecal digesta. Additionally, Zn‐POS supplementation increased gene expressions of metallothionein, Zn transporter 1, Zn transporter 2 in the pancreas, nuclear factor erythroid 2‐related factor 2 in the liver, the concentrations of acetate, propionate, butyrate and total SCFA in the caecal digesta and the villus height to crypt depth ratio in the duodenum and jejunum, whereas decreased the crypt depth in these two tissues. Altogether, our results revealed that dietary POS or Zn‐POS supplementation benefited growth performance, Zn status, antioxidant ability and gut function of broilers. Supplementing Zn‐POS in the form of chelate was more effective than feeding POS or ZnSO₄ separately.     

Modulation of ruminal and intestinal fermentation by medicinal plants and zinc from different sources

Two experiments were conducted on sheep to determine the effect of dietary supplementation with zinc and a medicinal plant mixture on haematological parameters and microbial activity in the rumen and large intestine. In Experiment 1, 24 male lambs were randomly divided into four groups: One group was fed an unsupplemented basal diet (control), and three groups were fed a diet supplemented with 70 mg Zn/kg diet in the form of Zn sulphate (ZnSO₄), a Zn‐chelate of glycine hydrate (Zn‐Gly) or a Zn‐proteinate (Zn‐Pro), for five months. The ruminal content was collected separately from each lamb, and batch cultures of ruminal fluid were incubated in vitro with mixture of medicinal plants (Mix) with different roughage:concentrate ratios (800:200 and 400:600, w/w). Bioactive compounds in Mix were quantified by UPLC/MS/MS. In Experiment 2, four sheep were fed a diet consisting of meadow hay and barley grain (400:600, w/w), with Zn‐Gly (70 mg Zn/kg diet), Mix (10% replacement of meadow hay) or Zn‐Gly and Mix (Zn‐Gly‐Mix) as supplements in a Latin square design. Mix decreased total gas (p < 0.001) and methane (p < 0.01) production in vitro. In Experiment 1, caecal isobutyrate and isovalerate concentrations varied among the dietary treatments (p < 0.01). The isovalerate concentration of the zinc‐supplemented groups in the distal colon was higher (p < 0.001) compared with the control. In Experiment 2, the molar proportion of isobutyrate was the highest in the faeces of the sheep fed the diet with Zn‐Gly‐Mix (p < 0.01). The plasma zinc concentration was higher in the groups fed a diet supplemented with zinc (p < 0.001). The haematological profile and antioxidant status did not differ between the dietary groups (p > 0.05). The diets containing medicinal plants and organic zinc thus helped to modulate the characteristics of fermentation in ruminants.     

Effect of dietary supplementation of organic zinc on laying performance,egg quality and some biochemical parameters of laying hens

This study was conducted to evaluate the effects of zinc methionine (Zn‐Met) supplementation on the performance, egg quality, antioxidant status and some biochemical parameters of blood serum in laying hens from 22 to 34 weeks of age. A total of 120 Hisex Brown laying hens of 22‐week‐old were randomly allocated into five treatments with six cage replicates for each (four hens/replicate). Dietary treatments consisted of the basal diet with no Zn‐Met supplementation (control group) and basal diet supplemented with 25, 50, 75 or 100 mg Zn‐Met/kg diet. No significant differences were observed on body weight, body weight gain or feed conversion ratio due to dietary Zn‐Met supplementation. However, highly significant impact was observed on daily feed intake. Egg number, egg weight and egg mass were increased in the group fed diet supplemented with the highest level of Zn‐Met (100 mg/kg of diet) as compared to other groups. All egg quality traits were statistically (p > .05 or .01) affected as a response to dietary Zn‐Met supplementation except egg shape index, shell percentage and yolk index. In comparison with the control group, dietary supplementation of 25, 50, 75 or 100 mg Zn‐Met/kg decreased serum triglyceride and LDL‐cholesterol levels. Serum cholesterol level was increased with all dietary levels of Zn‐Met in comparison with the control group. Dietary Zn‐Met supplementation increased the serum content of zinc, where the highest values were recorded with 50 and 100 mg Zn‐Met/kg diet. Dietary Zn‐Met levels did not affect the antioxidant indices in blood serum except for the activity of copper–zinc superoxide dismutase (Cu‐Zn‐SOD). The activity of Cu‐Zn‐SOD was increased with Zn‐Met supplementations with no differences among supplemental zinc levels. It is concluded that dietary Zn‐Met supplementation reduced serum triglyceride, LDL‐cholesterol and increased Zn status and resulted in promoting antioxidant ability of laying hens, and the addition of 100 mg Zn‐Met/kg to layer diet was appropriate for improving the above parameters in addition to egg production indices and Haugh unit score.     

Effect of dose and source of supplemental zinc on immune response and oxidative enzymes in lambs

An experiment of 150 days was conducted on 42 male Nellore lambs (28.3 ± 0.64 kg) to determine the effect of zinc (Zn) supplementation (0,15, 30 and 45 ppm) in diet from inorganic (ZnSO₄) and organic (Zn proteinate) sources on immune response and antioxidant enzyme activities by allotting them randomly to 7 groups in completely randomized design. The basal diet (BD) contained 29.28 ppm Zn. The humoral immune response assessed at 75 d against B. abortus was higher (P<0.01) with 15 or 30 ppm Zn supplementation from organic source. The dose and source had no effect on titres against chicken RBC antigen. The cell mediated immune response assessed as delayed type hypersensitivity (DTH) response against phytohaemagglutinin-P and in vitro lymphocyte proliferative response against concanavalin A at 150 d was higher (P<0.05) at 15 ppm Zn supplementation compared to BD fed lambs. Supplementation of 45 ppm Zn had no positive effect on immune response. The DTH response and antibody titres against B.abortus were higher (P< 0.05) on Zn proteinate compared to ZnSO₄ at 15 ppm Zn supplementation. The lipid peroxidase activity was lower (P < 0.01), while the RBC superoxide dismutase and catalase activities were higher (P < 0.01) in lambs at 15 ppm Zn supplementation compared to BD diet fed lambs, assessed at 75 d of feeding. Serum globulin concentration and alkaline phosphatase (ALP) activity (75 d of experiment) was higher in Zn supplemented lambs. The ALP activity increased (P < 0.01) with increase in Zn supplementation and being higher when supplementation was from Zn proteinate compared to ZnSO₄. The study indicated that 15 ppm zinc supplementation was required for obtaining higher immune response in lambs when fed a basal diet containing 29.28 ppm Zn and supplementation as Zn proteinate had higher antioxidant enzyme activities and immune response compared to ZnSO₄.     

Influence of different dietary zinc levels on cashmere growth,plasma testosterone level and zinc status in male Liaoning Cashmere goats

The experiment was conducted to investigate the influence of different levels of zinc (Zn) on cashmere growth, plasma testosterone and Zn profile in male Cashmere goats. Twenty‐eight male Liaoning Cashmere goats, 3 years old and body weight at 56.2 ± 2.45 kg, were assigned to four groups. The animals were fed a basal diet containing of 45.9 mg Zn/kg dry matter (DM) basis and supplemented with 0, 20, 40 or 80 mg Zn (reagent grade ZnSO₄·7H₂O) per kg DM for 90 days. There was no significant effect on growth and diameter of cashmere fibre for Zn supplemented in diets. However, the length and growth rate of wool were improved (p < 0.05) with dietary Zn. The length and growth rate of wool were higher (p < 0.05) for the groups supplemented with 40 or 80 mg Zn/kg DM compared with that of 20 mg Zn/kg DM treatment group. Plasma testosterone concentration was increased for Zn supplemented in diets, and the testosterone concentration was higher (p < 0.05) in goats fed on the diet supplemented with 40 or 80 mg Zn/kg DM compared with those fed on basal diet. Plasma Zn concentrations increased (p < 0.05) with increasing dietary Zn and supplemented with 40 and 80 mg Zn/kg DM groups improved plasma Zn concentration (p < 0.05) more than 20 mg Zn/kg DM group. Fibre Zn content was higher (p < 0.05) in groups supplemented with 40 or 80 mg Zn/kg DM compared with control group, but no difference between Zn‐supplemented groups (p > 0.05). The activity of plasma alkaline phosphatase was increased (p < 0.05) due to dietary Zn supplementation; however, no difference was found between supplemented treatment groups (p > 0.05). In conclusion, Zn content (45.9 mg Zn/kg DM) in control diet was insufficient for optimal wool growth performance, and we recommended the level of dietary Zn for such goats is 86 mg/kg DM during the breeding season and cashmere fibre growing period.     

Bioavailability of co‐supplemented organic and inorganic zinc and selenium sources in a white fishmeal‐based rainbow trout (Oncorhynchus mykiss) diet

The bioavailability of trace elements in fishmeal diets is influenced by their chemical forms and dietary anti‐nutritional factors. In formulated fish feed, supplemented organically bound minerals may be more bioavailable than inorganic minerals. A 10‐week feeding trial was undertaken with rainbow trout (Oncorhynchus mykiss) to determine whether the inclusion of organically bound selenium (Se) and zinc (Zn) improved uptake and assimilation of these elements compared to commonly used inorganic forms. The three diets tested included a control diet, no added Zn or Se; an organic Se‐yeast and Zn‐proteinate supplemented diet; and an inorganic sodium selenite and Zn‐sulphate supplemented diet. The endpoints tested were apparent digestibility, whole body levels, tissue distribution and Se‐ and Zn‐dependent enzyme activities. Digestibility of residual Se in the basal diet was 54.2 ± 1.0% and supplemented Se‐yeast was significantly more digestible than selenite (p < 0.05). Digestibility of residual Zn was 21.9 ± 2.0% and no significant difference was found between the treatments (p = 0.89). Whole body Se was raised by both Se sources and to a greatest extent by Se‐yeast (p < 0.001). Zn‐sulphate, and to a lesser extent Zn‐proteinate, both raised whole body Zn (p < 0.05). Dietary Zn in the basal diet was found to be above requirements, yet Zn‐sulphate had a significantly greater retention than Zn‐proteinate in those tissues that responded to Zn supplementation. Se‐yeast significantly raised Se in all tissues to a greater extent than selenite, except in the pyloric caeca and liver where the greatest increases were by selenite. Only Se‐yeast elevated Se‐dependent thioredoxin reductase activity (p < 0.05) and neither forms of Se affected glutathione peroxidise activity (p = 0.059). Alkaline phosphatase and carboxypeptidase B were not affected by Zn supplementation (p = 0.51 and p = 0.88 respectively). In all aspects, Se‐yeast was found to be a highly bioavailable form of Se in comparison to selenite. Because of its superior bioavailability, organically bound Se would be a preferred Se source for supplementation of fishmeal trout diets than selenite.     

Effects of supplemental palygorskite instead of zinc oxide on growth performance,apparent nutrient digestibility and fecal zinc excretion in weaned piglets

The aim of this study was to determine the effects of dietary supplementation of palygorskite instead of zinc oxide (ZnO) on growth performance, apparent nutrient digestibility and zinc contents in serum and feces in weaned piglets. One hundred and sixty‐five piglets (28 days of age, 7.10 ± 0.86 kg) were allotted to five treatments on the basis of weight and sex. Each treatment included three replicates of 11 piglets. The piglets were fed the same basal diet supplemented with 0 mg/kg (control group), 1800 mg/kg, 2400 mg/kg, or 3000 mg/kg palygorskite or 2500 mg/kg ZnO for 28 days. There was no significant difference for incidence of diarrhea among the four treatments during the 0–14‐day feeding period. Compared with the control group, piglets offered diets supplemented with 1800 mg/kg palygorskite had higher (P < 0.05) average daily gain (ADG) and crude protein digestibility. Fecal digestibility of energy in 1800 mg/kg palygorskite and ZnO groups were higher (P < 0.05) than that in the control group. Both the zinc concentrations in serum and fecal zinc excretion in palygorskite groups and control group were all lower (P < 0.05) than that in the ZnO group. In conclusion, dietary supplementation with 1800 mg/kg palygorskite can improve growth performance and nutrient digestibility and can also decrease zinc excretion in feces in weaned piglets.     

Bitter vetch as a single dietary ingredient for molt induction in laying hens

Molting is used to increase productivity in the second laying cycle of commercial laying flocks. We report here the applicability of whole grain of bitter vetch as an alternative method for molt induction in laying hens. A total of 120 laying hens were molted by feed withdrawal (FW), a high-Zn diet (HZn), a moderate-Zn and Ca-P-deficient diet (MZn-CaP), or whole grain of bitter vetch (BV). Egg production ceased first in FW-treated hens and last in MZn-CaP-treated hens (P < 0.05). The rest period was longer (P < 0.05) in hens exposed to the BV diet, which proved to be comparable with the FW treatment for postmolt egg production. Egg mass for 4 to 16 wk after the molting was greater (P < 0.05) for hens molted by BV than hens molted by the MZn-CaP diet. Egg weight and yolk color were not (P > 0.05) significantly different among various molting induction methods. Albumen height and Haugh unit of eggs from hens molted by BV, for the most part of the experimental period, were significantly (P < 0.05) greater than for birds on the MZn-CaP diet and unmolted hens. In conclusion, use of BV grain as a single dietary ingredient proved to be effective in molt induction and improving postmolt egg production and internal egg quality when compared with unmolted hens.     

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low‐crude‐protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L‐Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57–0.66%. In addition, serum‐free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low‐CP diet compared with hens fed CP (16.18%) and hens fed 0.57–0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF‐γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL‐2, IL‐6, IL‐1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low‐crude‐protein diet of laying hens during the peak production period.     

Organic trace minerals on productive performance,egg quality and immune response in Bovans White laying hens

This study was performed in 360 laying Bovans White hens and aimed to evaluate the effect of Carbo‐Amino‐Phosphate‐Chelates (CAFQ) as a mineral premix and its 30% reduction by compared to inorganic trace minerals (ITM) concerning its performance, egg quality, tibia breaking strength and immunity. Sixty‐week‐old hens were assigned into three treatments with 10 replicates of 12 birds each. Treatments were as follows: (a) (100% ITM), (b) (100% CAFQ) and (c) (70% CAFQ). Based on the results obtained during 12 weeks, under the current test conditions, improved yolk colour (p < 0.05); shell breaking strength (p < 0.05); and storage time (p < 0.05) were observed in hens fed with a diet reduced by 70% in CAFQ inclusion showed similar performance behaviour and better egg breaking strength regarding with ITM, suggesting the possibility of minimizing the inclusion of trace minerals in laying hen diets improving environmental impact, in contrast to the use of inorganic sources of minerals.     

乳酸锌对蛋鸡生产性能及蛋壳质量的影响

为研究乳酸锌对蛋鸡生产性能及蛋壳质量的影响,试验采用单因子随机分组试验设计,选取1600只360日龄的罗曼粉壳蛋鸡,随机分为4个处理组,每个处理组8个重复,每个重复50只鸡。础饲日粮为玉米-豆粕型粉状饲粮,处理1组饲喂基础饲粮+60 mg/kg一水硫酸锌(以锌计),处理2组饲喂基础饲粮+60 mg/kg乳酸锌(以锌计),处理3组饲喂基础饲粮+40 mg/kg乳酸锌(以锌计),处理4组饲喂基础饲粮+60 mg/kg锌(一水硫酸锌和乳酸锌提供的锌各一半)。结果表明,蛋鸡日粮中添加60 mg/kg乳酸锌(以锌计)能显著降低平均破蛋率、提高平均蛋壳强度(P<0.05)和明显提高平均蛋壳厚度,并且平均死亡率最低,但对蛋鸡的平均产蛋率、平均蛋重、平均日采食量和平均料蛋比无显著影响(P>0.05)。     

Effect of expanded cottonseed meal on laying performance,egg quality,concentrations of free gossypol in tissue,serum and egg of laying hens

Three hundred and sixty Hy‐Line Brown hens, 40 week of age, were allocated to five treatments, each of which included four replicates of 18 hens. After an expanded process of cottonseed meal (CSM), free gossypol content in CSM was decreased from 1.24 to 0.40 g/kg. The dietary treatments were corn‐soybean meal based diets including 6% CSM and 6%, 8% and 10% expanded cottonseed meal (ECSM). Hens fed 8% ECSM had higher (P < 0.05) laying rate and average egg weight than those fed 6% CSM. The albumen height and Haugh unit in the control group, 6% and 8% ECSM groups were superior (P < 0.05) to other treatments. Hens fed 6% CSM resulted in severe (P < 0.05) egg yolk discoloration. Free gossypol (FG) concentrations in yolk and albumen and tissues of the 6% CSM group were greater (P < 0.05) than those in any ECSM treatments. Hens fed 6% CSM and 10% ECSM had the highest (P < 0.05) FG concentrations in the liver compared with those in the kidney and muscle, and higher (P < 0.05) FG residues in yolk than those in albumen. In conclusion, FG in CSM can be reduced by 68% through an expanded process and ECSM can be available in laying hens at up to 10% of the total diet and an appropriate replacement of soybean meal with ECSM may improve performance in laying hens.     

Supplementation of diets for lactating sows with zinc amino acid complex and gastric nutriment‐intubation of suckling pigs with zinc methionine on mineral status,intestinal morphology and bacterial translocation in lipopolysaccharide‐challenged weaned pigs

Sixty‐four pigs from 16 sows were used to evaluate addition of zinc amino acid complex (ZnAA) to lactating sows and gastric nutriment‐intubation of zinc methionine (ZnMet) to suckling pigs on mineral status, intestinal morphology and bacterial translocation after weaning. Sows were fed a barley‐based diet supplying 120 ppm zinc (Zn; control) or the control diet supplemented with 240 ppm Zn from ZnAA. At birth, day‐10 and day‐21 (weaning) of age, pigs from each litter were nutriment‐intubated with 5 ml of an electrolyte solution without or with 40 mg Zn from ZnMet. At weaning, 24 h prior to the collection of small and large intestinal lymph nodes and sections of the duodenum, jejunum and ileum, the pigs received an intramuscular injection of saline without or with 150 μg/kg body weight of Escherichia coli O26:B6 lipopolysaccharide (LPS). With the exception of a tendency (p = 0.09) for lower serum concentration of copper in pigs at weaning from ZnAA‐supplemented sows, there were no differences (p > 0.1) than for pigs from control‐fed sows for mineral status or intestinal morphology. Nutriment‐intubation of ZnMet increased serum (p = 0.001) and liver (p = 0.003) Zn concentrations, number of goblet cells per 250 μm length of jejunal villous epithelium (p = 0.001) and tended (p = 0.06) to enhance jejunum mucosa thickness. Interactive effects (p < 0.05) for higher jejunal villi height and villi:crypt ratio and increased ileal goblet cell counts were apparent for pigs from ZnAA‐supplemented sows that also received nutriment‐intubation of ZnMet. Challenge with LPS increased (p = 0.05) ileal villous width. Nutriment‐intubation of ZnMet decreased (p = 0.05) anaerobic bacteria colony forming unit counts in the large intestinal mesenteric lymph nodes. In conclusion, nutriment‐intubation of ZnMet increased serum and liver tissue concentrations of Zn and resulted in limited improvement to intestinal morphology of weaned pigs.     

Effects of iron glycine chelate on laying performance,antioxidant activities,serum biochemical indices,iron concentrations and transferrin mRNA expression in laying hens

This study was conducted to evaluate the effects of iron glycine chelate (Fe‐Gly) on laying performance, antioxidant enzyme activities, serum biochemical indices and iron concentrations in laying hens. A total of 810 laying hens (Hy‐Line Variety White, 26 weeks old) were randomly assigned to six groups with five replicates of 27 layers. Hens in the control group received diet supplemented with 60 mg Fe/kg as FeSO₄, while hens in other five groups received the diet supplemented with 0, 20, 40, 60 and 80 mg Fe/kg from Fe‐Gly respectively. The results showed that dietary Fe‐Gly treatments significantly influenced (p < 0.01) the laying rate and egg weight of layers, compared with the control group. Concerning to CuZn‐superoxide dismutase (CuZn‐SOD) and total superoxide dismutase (T‐SOD) activity, Fe‐Gly groups (60, 80 mg Fe/kg) were promoted significantly (p < 0.01) compared with 0 mg Fe/kg group. The concentrations of Fe in serum, liver, kidney, spleen and ovary were increased significantly with the level dietary Fe‐Gly raised where Fe‐Gly groups (60, 80 mg Fe/kg) had observably higher Fe concentration than the control (p < 0.01) in serum, kidney and spleen. There was a trend that transferrin mRNA expression was decreased with the increase of Fe as Fe‐Gly in diets, and compared with the control, the expression was lower in the group fed diet with 60 mg/kg Fe as Fe‐Gly. In conclusion, Fe‐Gly (60 mg Fe/kg) had improved laying rate, egg weight, SOD enzyme activity, Fe absorption and protein synthesis in body and promoted iron metabolism in laying hens. Moreover, Fe‐Gly (40 mg/kg Fe) had the similar effect with control group. It revealed that FeSO₄ could be substituted by lower concentration of Fe‐Gly and Fe‐Gly may be superior to FeSO₄ for iron fortification to laying hens.     

Live Performance and Immune Responses of Straight-Run Broilers: Influences of Zinc Source in Broiler Breeder Hen and Progeny Diets and Ambient Temperature During the Broiler Production Period

Supplemental zinc in broiler diets has been reported to be more available to the chick when provided as a zinc-amino acid complex rather than an inorganic source. Previous work with broiler breeder and turkey hens has indicated that supplementing diets with zinc-amino acid complexes enhances immune status and livability of progeny. This study examined the effects of supplemental dietary zinc source [ZnSO₄ or Availa Zn 100 zinc-amino acid complex (ZnAA)] provided to broiler breeder hens and their progeny on live performance and immune status of broilers. Broiler breeder and progeny diets were supplemented with 160 and 140 ppm zinc, respectively. In addition to the dietary treatments, the broilers were subjected to either optimum or suboptimum temperatures during the first weeks of production. Supplementing broiler breeder hen and progeny diets with ZnAA and ZnAA + ZnSO₄, respectively, improved cumulative feed conversion (FC) of broilers. Providing diets supplemented with ZnSO₄ to hens or exposing broilers to optimum temperatures enhanced humoral immune response of progeny. Subjecting broilers to suboptimum brooding temperatures increased feed intake, but a higher incidence of mortality occurred primarily encompassing the first week of the growout. These data indicate that brooding temperature affected broiler performance, whereas the response to dietary zinc source was less pronounced.     

Neem (Azadirachta indica) kernel meal in the diet of White Leghorn layers

1. Neem kernel meal (NKM) was incorporated into a standard layer diet at 0, 100, 150 and 200 g/kg, replacing parts of the soyabean meal and deoiled rice bran. Each diet was offered to 18 White Leghorn layers (25 weeks, 50% egg production) in individual cages for a period of 12 weeks. 2. Results indicated significantly lower food intakes (P<0.01), rates of egg production and egg weights in birds fed on the diets with NKM at 150 and 200 g/kg. Fertility and hatchability were also adversely affected by the higher inclusion rates of NKM. 3. Except for lower egg shell weight and shell thickness (P<0.05) in hens fed NKM at 150 and 200 g/kg, the internal egg quality characteristics were comparable in all groups. 4. Feeding NKM beyond 100 g/kg to laying hens significantly (P<0.01) reduced the content of haemoglobin, erythrocyte count, packed cell volume, serum calcium and uric acid concentrations. However, the leucocyte count, plasma glucose concentration and serum glutamate oxaloacetate transaminase activity were unaltered. Serum glutamate pyruvate transaminase activity was significantly (P<0.05) reduced in birds fed NKM at 200 g/kg. 5. Thus NKM at 100 g/kg in a layer diet would appear to be safe and cost-effective.