Effects of dietary sorghum dried distiller's grains with solubles on growth performance,diet nutrient digestibility,carcass characteristics and immunity in growing rabbits

Sorghum dried distiller's grains with solubles (S‐DDGS) are distillation extract residues from the ethanol fuel industry. In this experiment, two hundred 42‐day‐old rabbits were randomly allocated to five experimental diets containing 0 g/kg (control), 75, 150, 225 and 300 g/kg S‐DDGS. The experiment lasted for 4 weeks. No difference was found in the average daily feed intake (ADFI; p > 0.05). With increasing sorghum inclusion, the average daily gain (ADG) was linearly (p < 0.001) and quadratically (p = 0.039) reduced, while, conversely, the feed conversion ratio (FCR) linearly (p < 0.001) increased. Increasing the amount of S‐DDGS in the diet linearly decreased (p < 0.001) the apparent total tract digestibility (ATTD) of dry matter (DM), organic matter (OM), crude protein (CP) and ash. Carcass weight, carcass yield, heart and liver weights were linearly decreased by an increase in the amount of S‐DDGS added to diets (p < 0.001), but no difference was observed between the 0, 75 and 150 g/kg S‐DDGS groups (p > 0.05). Serum IL‐6, IL‐10 and SIgA linearly increased (p = 0.008) with increasing levels of S‐DDGS in the diet. Rabbits fed 0, 75 and 150 g/kg of S‐DDGS had similar IL‐6 and IL‐10 levels. Statistically significant differences in SIgA were observed between rabbits fed control diets and feed mixtures containing S‐DDGS (p < 0.01). To conclude, S‐DDGS can safely be added up to 75 g/kg, to the diet of rabbits. Increasing dietary S‐DDGS inclusion may decrease the growth performance, nutrient digestibility and carcass traits, and activate immune responses.     

Effect of a dietary supplementation with linseed oil and selenium to growing rabbits on their productive performances,carcass traits and fresh and cooked meat quality

The present experiment tested a dietary supplementation with linseed oil and selenium to growing rabbits. The basal diet (B) contained 3% sunflower oil, while it was substituted with 3% linseed oil in the experimental feed (S). The selenium (Se) content of the two diets was 0.10 vs. 0.46 mg/kg. Rabbits were fed with B diet from the age of 18 days. One group was fed with the B diet until 11 weeks of age (group B), whereas the experimental groups were fed with S diet for 1, 2, 3 or 4 weeks (groups S1, S2, S3 and S4, respectively), before slaughtering (11 weeks of age). Live performance and carcass traits of rabbits, fatty acid (FA) profile and selenium content of their hind leg (HL) and Longissimus thoracis et lumborum (LTL) meat were considered in this study. In addition, the effect of two different cooking methods on the nutritional value of the enriched HL meat was also assessed. The tested dietary supplementation only minimally affected the live performance and carcass traits of rabbits. The S supplementation significantly reduced the Σ n‐6 FA and increased the Σ n‐3 FA of the HL meat and LTL meat, compared to the B diet (p < 0.001); thus, n‐6/n‐3 ratio was improved (p < 0.001). In addition, HL meat and LTL meat of S fed rabbits were significantly enriched in Se reaching a twofold increase in both meat cuts (p < 0.01). Therefore, the S supplementation improved the functional value of the rabbit meat. The heat treatment affected cooking loss, Se and vitamin E contents as well as the oxidative status of the HL meat (p < 0.001), with the different cooking methods providing different results. In addition, even if the beneficial C20:5 n‐3 and C22:6 n‐3 decreased with cooking, the n‐6/n‐3 ratio remained unaffected.     

Improving effects of dietary rumen protected γ‐aminobutyric acid additive on apparent nutrient digestibility,growth performance and health status in heat‐stressed beef cattle

This study was aimed to investigate the effects of rumen‐protected γ‐aminobutyric acid (RP‐GABA) on apparent nutrient digestibility, growth performance and health status in heat stressed beef cattle. Fifty Jinjiang Yellow cattle were randomly assigned to 5 treatments (10 animals/treatment). Treatments 1 to 5 were basal diets affixed with 0 (control), 8, 16, 24 and 32 mg of RP‐GABA/kg of body weight (BW) respectively. The trial lasted 45 days. Apparent digestibility of crude protein (CP), crude fiber (CF) and calcium (Ca) quadratically increased with increasing RP‐GABA (p < .01), while apparent digestibility of phosphorus (P) tended to quadratically increase (p = .09). Dietary supplementation with increasing RP‐GABA linearly increased DM digestibility and average daily gain (ADG) (p < .01), whereas the feed to gain (F:G) ratio linearly decreased with increasing RP‐GABA (p < .01). The average daily feed intake (ADFI) value tended to linearly increase with RP‐GABA supplementation (p = .08). Total protein (TP), blood urea nitrogen (BUN) and malondialdehyde (MDA) levels quadratically decreased (p < .01) with increasing RP‐GABA, however albumin (ALB), glucose (GLU), superoxide dismutase (SOD), triiodothyronine (T3) and thyroxine (T4) levels quadratically increased (p ≤ .01). In conclusion, the present results indicated that dietary supplementation with RP‐GABA led to improved nutrient digestibility, growth performance and antioxidant status in heat stressed beef cattle.     

Effects of dietary supplementation with betaine on muscle growth,muscle amino acid contents and meat quality in Cherry Valley ducks

The effects of dietary betaine supplementation on growth performance, carcass characteristics, muscle amino acid contents, meat quality, antioxidant capacity, myogenic gene expression and mechanistic target of rapamycin (mTOR) signalling pathway in Cherry Valley ducks were evaluated. A total of 720 1‐day‐old Cherry Valley ducks were randomly distributed into four groups with six replicates of 30 birds for a 42‐day feeding trial. Ducks were fed a basal diet supplemented with 0 (control), 250, 500 or 1,000 mg/kg betaine, respectively. Growth performance was not affected by betaine. Incremental levels of betaine linearly (p < 0.05) increased the breast muscle yield and linearly (p < 0.05) decreased the subcutaneous fat thickness and the abdominal fat yield. The contents of methionine, serine, glycine, glutamate and total non‐essential amino acid in breast muscle were linearly (p < 0.05) increased by betaine supplementation. With increasing betaine levels, the drip loss and the content of malondialdehyde (MDA) were linearly (p < 0.05) decreased, and the redness of meat (linear p < 0.05), the activities of catalase (CAT) (linear p < 0.05) and total superoxide dismutase (T‐SOD) (linear p < 0.05, quadratic p < 0.05) were increased. Moreover, the myogenic differentiation factor 1 (MyoD1) mRNA expression and the mTOR mRNA expression and protein phosporylation were linearly (p < 0.05) up‐regulated, and the myostatin (MSTN) mRNA expression was linearly (p < 0.05) down‐regulated by betaine supplementation. Overall, this study indicated that betaine supplementation did not affect the growth performance of Cherry Valley ducks, but could linearly increase some amino acid contents in breast muscle, especially glycine, and increase muscle antioxidant activity to improve meat quality. Moreover, betaine supplementation could improve the breast muscle yield by increasing MyoD1 mRNA expression, decreasing MSTN mRNA expression and regulating mTOR signalling pathway.     

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.     

Effects of different levels of sanguinarine on antioxidant indices,immunological responses,ileal microbial counts and jejunal morphology of laying hens fed diets with different levels of crude protein

This study was carried out to assess the effects of different levels of sanguinarine on antioxidant indices, immunological responses, serum biochemical parameters, ileal microbial counts and jejunal morphology of laying hens fed on diets with different levels of crude protein (CP). A total of 180 laying hens were subjected into nine dietary treatments with four cages of five birds each. Experimental treatments consisted of three levels of CP (85.0, 92.5 and 100% of Hy‐Line W36 manual recommendation) and three levels of sanguinarine (0.00, 3.75 and 7.50 mg/kg) as a 3 × 3 factorial arrangement of laying hens which fed during a 70‐day feeding trial. The in vitro study showed that sanguinarine exhibited sevenfold and threefold decreased antioxidant activities to inhibit 2‐2‐diphenyl‐1‐picric hydrazyl free radical as well as ferric ion reducing rather than butylated hydroxyl toluene. Although using the decremental levels of CP caused the increase in heterophil‐to‐lymphocyte ratio (p < 0.01), dietary administration of sanguinarine could suppress the serum cholesterol and malondialdehyde concentrations as well as heterophil‐to‐lymphocyte ratio (p < 0.05). Additionally, decreasing CP content resulted in the decreased percentage of albumin (p < 0.05); however, it had no negative effects on humoral immunity. Nonetheless, feeding of at least 3.75 mg/kg sanguinarine led to the remarkable increases in serum gamma globulin concentration (p < 0.01) and secondary (p < 0.05) antibody titres against sheep red blood cells. Moreover, a decline in dietary CP content led to higher villi height and crypt depth (p < 0.05; p < 0.001) and consequently decreased villi height‐to‐crypt depth ratio (p < 0.001) than the optimum level (100% CP). In spite of the effects of sanguinarine on the suppression of Escherichia coli and Salmonella counts (p < 0.05), it markedly enhanced villi height‐to‐crypt depth ratio as well as lamina propria lymphatic follicles extent, simultaneously (p < 0.001). Therefore, in spite of the detrimental effects of feeding low‐CP diets on lymphocytes and serum albumin percentages, and villi height‐to‐crypt depth ratio, the administration of incremental levels of sanguinarine could improve cellular and humoral immunity, decrease ileal microbial counts and in turn improve the intestinal health indices in laying hens.     

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.     

Effects of Moringa oleifera leaves as a substitute for alfalfa meal on nutrient digestibility,growth performance,carcass trait,meat quality,antioxidant capacity and biochemical parameters of rabbits

This contribution reports the effects of Moringa oleifera leaves (MOLs) meal on the growth performances, nutrient digestibility, carcass trait, meat quality, antioxidant capacity and biochemical parameters of growing New Zealand white rabbits. The MOL was substituted for alfalfa meal at levels of 0, 10%, 20% and 30% to obtain respective diets MOL0, MOL10, MOL20 and MOL30. Each treatment was replicated five times with 10 rabbits per replicate. Results showed the average daily weight gain (ADWG) and feed conversion ratio (FCR) of rabbits fed MOL20 diet were significantly better (p < 0.05) than those of other three dietary groups. Liver and spleen index of rabbits fed MOL20 and MOL30 diets was significantly higher (p < 0.05) than that of the groups fed with lower M. oleifera leaves (MOL0, MOL10). The meat drip loss of rabbits fed with diet MOL10 was significantly lower (p < 0.05) than that of rabbits fed other diets. All rabbits fed MOL dietary groups had lower (p < 0.05) shear force of longissimus dorsi than the group without M. oleifera leaves. No significant differences were found in the digestibility of crude fibre (CF), crude fat (EE), ash, crude protein (CP) and nitrogen‐free extract (NFE) among the dietary groups. Moringa oleifera leaves also have a significant impact on serum albumin (ALB), low‐density lipoprotein cholesterol (LDLC), triiodothyroxine (T₃) and tetraiodothyroxine (T₄) values and the activity of superoxide dismutase (SOD) and catalase (CAT) in serum and liver. The results indicated that M. oleifera leaves could be developed as a good feed source, and it not only could substitute for alfalfa meal well but also has a significant effect on growth performance, meat quality, antioxidant and biochemical parameters of rabbits.     

Effects of age and zinc supplementation on transport properties in the jejunum of piglets

Zinc is effective in the prevention and treatment of post‐weaning diarrhoea and in promoting piglet growth. Its effects on the absorption of nutrients and the secretory capacity of the intestinal epithelium are controversial. We investigated the effects of age, dietary pharmacological zinc supplementation and acute zinc exposure in vitro on small‐intestinal transport properties of weaned piglets. We further examined whether the effect of zinc on secretory responses depended on the pathway by which chloride secretion is activated. A total of 96 piglets were weaned at 26 days of age and allocated to diets containing three different levels of zinc oxide (50, 150 and 2500 ppm). At the age of 32, 39, 46 and 53 days, piglets were killed, and isolated epithelia from the mid‐jejunum were used for intestinal transport studies in conventional Ussing chambers, with 23 μm ZnSO₄ being added to the serosal side for testing acute effects. Absorptive transport was stimulated by mucosal addition of d ‐glucose or l ‐glutamine. Secretion was activated by serosal addition of prostaglandin E₂, carbachol or by mucosal application of Escherichia coli heat‐stable enterotoxin (St_p). Jejunal transport properties showed significant age‐dependent alterations (p < 0.03). Both absorptive and secretory responses were highest in the youngest piglets (32 d). The dietary zinc supplementation had no significant influence on jejunal absorptive and secretory responses. However, the pre‐treatment of epithelia with ZnSO₄ in vitro led to a small but significant decrease in both absorptive and secretory capacities (p < 0.05), with an exception for carbachol (p = 0.07). The results showed that, in piglets, chronic supplementation with zinc did not sustainably influence the jejunal transport properties in the post‐weaning phase. Because transport properties are influenced by the addition of zinc in vitro, we suggest that possible epithelial effects of zinc depend on the acute presence of this ion.     

Effect of resveratrol on growth performance,rectal temperature and serum parameters of yellow‐feather broilers under heat stress

This study investigated the effect of dietary resveratrol supplementation on growth performance, rectal temperature, and serum parameters of yellow‐feather broilers under heat stress. A total of 480 yellow‐feather broilers (28‐day‐old) were randomly allotted to five groups with six replicates. A thermoneutral group (TN) (24 ± 2°C) received a basal diet and another four heat‐stressed groups (37 ± 2°C for 8 hr/day and 24 ± 2°C for the remaining time) were fed the basal diet or basal diet with 200, 350, and 500 mg/kg resveratrol for 14 consecutive days. The results revealed that resveratrol supplementation improved average daily gain (p = 0.001), and decreased (p < 0.05) rectal temperature from d 3 when compared with heat‐stressed group without resveratrol. In addition, supplementation with resveratrol at 350 or 500 mg/kg lowered (p < 0.05) the contents of corticosterone, adrenocorticotropic hormone, cholesterol, triglycerides, uric acid, malonaldehyde, and activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, increased (p < 0.05) the levels of triiodothyronine, the ratio of triiodothyronine to thyroxine, total protein, glutathione, and activities of alkaline phosphatase, total superoxide dismutase, catalase, and glutathione peroxidase, though with few fluctuation. In conclusion, supplementation with resveratrol can improve the growth performance by positively regulating serum metabolic parameters and alleviating tissue oxidant damage of broilers under heat stress.     

Montmorillonite improved the intestinal mucosal barrier functions of laying hens in late production

This study was conducted to investigate the effects of dietary supplementation with montmorillonite (MMT) on performance, intestinal endotoxin concentration, gut mucosal oxidation status, intestinal morphology and permeability, and immunological barrier function of laying hens during late production. Four hundred and eighty 75‐week‐old laying hens (Lohmann Brown) were randomly assigned to five treatments with eight replicates per treatment and 12 hens in each replicate. The hens were fed the basal diet supplemented with 0 (control), 0.3, 0.6, 0.9, or 1.2 g MMT/kg for 70 days. Compared with the control, supplemented with 0.9 g MMT/kg increased egg mass significantly (p < 0.05) during weeks 1–5 of the experiment. Supplemented with 0.6 and 0.9 g MMT/kg also increased the endotoxin concentration in the ileal digesta (p < 0.05), but decreased the MDA concentration in the ileum significantly (p < 0.05). The T‐AOC in the jejunum of the group fed 0.3 g MMT/kg was significantly increased (p < 0.05). Compared with the control, the villus height:crypt depth of ileum from the groups fed 0.6, 0.9, and 1.2 g MMT/kg increased significantly (p < 0.05). The sIgA concentration of jejunum in the groups fed 0.6 and 0.9 g MMT/kg was higher (p < 0.05) than the control. The MMT supplementation linearly increased (p < 0.05) the mRNA expression of claudin‐1 and claudin‐5 in the jejunum. Dietary MMT supplementation down‐regulated the mRNA expression of NF‐κB P65 and TNF‐α in the jejunum in a linear and quadratic manner (p < 0.05). The IL‐1β mRNA expression of jejunum in the group fed 0.6 g MMT/kg was lower (p < 0.05) than the control. In conclusion, dietary supplementation with MMT may improve the gut barrier functions and suggests that 0.9 g/kg of MMT in diets may be the optimal supplemental level for laying hens in late production.     

Effects of vitamin E supplementation on performance,serum biochemical parameters and fatty acid composition of egg yolk in laying hens fed a diet containing ageing corn

This study investigated whether dietary vitamin E (VE) supplementation could alleviate any detrimental effects of ageing corn in the diet for laying hens on egg performance, egg quality, serum biochemical parameters, cholesterol content and the fatty acid (FA) profile of egg yolks. The experiment consisted of a 2 × 3 factorial design with two corn types (normal corn and ageing corn) and three concentrations of VE (0, 20 and 100 IU/kg). A total of 216 Lohmann laying hens (50‐week‐old) were randomly allocated into six treatment diets for 12 week. Each treatment had six replicates with six hens. The results showed that ageing corn significantly reduced average daily feed intake (ADFI; p < 0.01) and egg weight (p < 0.05). Dietary VE supplementation had no significant influences on egg production performance (p > 0.05). Egg yolk colour was decreased in ageing corn diets (p < 0.01), while 20 and 100 IU/kg VE significantly improved vitelline membrane strength (p < 0.01) compared with feeding of 0 IU/kg VE. Ageing corn also significantly decreased the content of cholesterol including total cholesterol (TC; p < 0.05), low density lipoprotein cholesterol (LDL‐C; p < 0.01) and very low density lipoprotein cholesterol (VLDL‐C; p < 0.05) in the serum. Feeding 100 IU/kg VE significantly increased the content of LDL‐C (p < 0.01) and VLDL‐C (p < 0.05) in the serum. Furthermore, the content of the oleic acid, docosahexaenoic acid and total monounsaturated fatty acid (MUFA) was lower (p < 0.05) and stearic acid and total saturated fatty acid (SFA) was higher (p < 0.05) in egg yolks in ageing corn diets. Ageing corn resulted in reduced feed intake, egg weights and yolk colour, but the effects of VE supplementation were independent of those of age of corn and were unable to counteract the negative effects of feeding ageing corn.     

Effect of different levels of black cumin (Nigella sativa L.) on performance,intestinal Escherichia coli colonization and jejunal morphology in laying hens

This study was conducted to investigate the effects of different levels of black cumin seeds (Nigella sativa L.) on performance, intestinal Escherichia coli count and morphology of jejunal epithelial cells in laying hens. A total of 100 Leghorn laying hens (Hy‐Line W‐36) of 49 weeks old were randomly distributed among five cage replicates of five birds each. Experimental diets consisted of different levels (0%, 1%, 2% and 3% of diet) of dietary black cumin inclusion. The experimental period lasted for a total of 10 weeks, and egg quality indexes and laying hens' performance were measured as two 35‐day trial periods. At the final day, two hens per replicate were slaughtered to investigate the influence of dietary treatments on intestinal E. coli colonization and morphology of jejunal cells. Although dietary black cumin in all supplementation levels decreased (p < 0.05) the enumeration of ileal E. coli, the morphological and histological alterations in small intestine such as enhancement of villus height to crypt depth ratio, increased goblet cell numbers and proliferation of lamina propria lymphatic follicles were observed after dietary supplementation with at least 2% black cumin. Dietary treatments decreased (p < 0.05) the concentration of serum cholesterol and triglycerides and increased (p < 0.05) serum HDL concentration and relative weight of pancreas; however, the egg yolk cholesterol was not influenced by dietary treatments. In addition, dietary supplementation with black cumin improved (p < 0.05) eggshell quality and Haugh unit. The best feed conversion ratio was obtained when diets were supplemented with 2% black cumin. This improvement was due to the increase (p < 0.05) in egg mass and contemporaneous decrease (p < 0.01) in feed consumption. The present results indicated that regardless of supplementation level, dietary inclusion of black cumin decreased E. coli enumeration in ileal digesta and improved serum lipid profile and eggshell quality, whereas the best intestinal health indices and haying hens' performance were obtained by at least 2% black cumin seeds.     

Effects of dietary phytoncides extracted from Korean pine (Pinus koraiensis) cone on performance,egg quality,gut microflora,and immune response in laying hens

This study was conducted to evaluate the effects of dietary phytoncides extracted from discarded Korean pine cones (Pinus koraiensis) on the performance, egg quality, immune response and gut microflora in laying hens. A total of 400 Hy‐Line brown laying hens (50‐week old) were allotted into four dietary treatments including a control diet or a diet supplemented with phytoncides at 0.002%, 0.004% and 0.008%. During the 6 weeks of experimental feeding, 0.008% of dietary phytoncides improved egg production, feed conversion ratio (p < 0.05), but not feed intake, egg weight or feed efficiency. Although dietary phytoncides had no effect on egg quality, decreases in Haugh units depending on storage periods were improved by 0.008% of dietary phytoncides (p < 0.05). To investigate the roles of dietary phytoncides on the alteration of the immune response during inflammation, lipopolysaccharide (LPS) or saline was intraperitoneally injected into 10 hens per diet group on the end date of the experimental feeding period. Serum immunoglobulins and splenic cytokine expression at mRNA levels were then measured at 4 hr postinjection. Although the levels of IgA were decreased by LPS injection in all dietary groups, dietary phytoncides at 0.008% showed a higher level of IgA by LPS (p < 0.05). Interestingly, although LPS injection resulted in an enhanced expression of proinflammatory cytokines such as IL‐1β and IL‐6, dietary phytoncides at 0.008% showed less increased levels of them (p < 0.05). Gut microflora was examined from 10 hens per diet group at the end of the experimental period. While the number of Lactobacillus spp. was increased (p < 0.05), Escherichia coli counts in the cecal contents were decreased by 0.008% of dietary phytoncides. Taken together, these results demonstrate that dietary supplementation of 0.008% phytoncides improved the egg production, immune responses during inflammation and gut microflora in laying hens.     

Effects of milk thistle meal on performance,ileal bacterial enumeration,jejunal morphology and blood lipid peroxidation in laying hens fed diets with different levels of metabolizable energy

This study was conducted to evaluate the effects of different levels of milk thistle meal on performance, blood biochemical indices, ileal bacterial counts and intestinal histology in laying hens fed diets containing different levels of metabolizable energy. A total number of 200 Leghorn laying hens (Hy‐Line W‐36) were randomly assigned to eight experimental treatments with five cage replicates of five birds each. Dietary treatments consisted of four levels of milk thistle meal (0%, 15%, 30% and 60%) and two levels of AME_n (11.09 and 12.34 MJ/kg) fed over a period of 80 days. In vitro studies revealed that the total phenolic component of milk thistle meal was 470.64 mg gallic acid equivalent/g of the sample, and its antioxidant activity for inhibiting the 2‐2‐diphenyl‐1‐picrichydrazyl free radical and reducing ferric ions was about 21% higher than that of butylated hydroxyltoluene (p < .05). Diets containing high level of AME_n led to improved egg production (p < .05), egg weight (p < .05), egg mass (p < .01) and feed conversion ratio (p < .01). In addition, offering diets containing high energy significantly enhanced (p < .01) serum triglyceride and malondialdehyde (MDA) concentrations as well as jejunal villus height. Dietary supplementation of 3% milk thistle meal resulted in the best feed conversion ratio (p < .05), reduction of ileal Escherichia coli enumeration (p < .01) and an enhancement in the villus height‐to‐crypt depth ratio (p < .05). Furthermore, feeding incremental levels of this meal led to remarkable decrease in serum cholesterol, triglyceride and MDA (p < .01) concentrations while significant increase in blood high‐density lipoprotein content and goblet cell numbers (p < .05). The present findings indicate that milk thistle meal with high antioxidant and antibacterial properties in laying hen diets may improve health indices and productive performance.     

Marginal deficiencies of dietary arginine and methionine could suppress growth performance and immunological responses in broiler chickens

The present study was conducted to investigate the effects of different levels of dietary arginine (Arg) and methionine (Met) on performance, immune responses, and carcass characteristics of broiler chickens. A total of 540 day‐old Ross 308 broiler chicks were randomly assigned into the nine experimental diets, consisting five replicates of 12 birds each. Dietary treatments included three different levels (90%, 100%, and 110% of National Research Council [NRC] specifications) of either dietary Arg or Met, which were fed to the birds according to a 3 × 3 factorial arrangement of treatments during a 42 days feeding trial. Results showed that supplementation of Arg and Met into the deficient‐diets increased (p < .01) weight gains during all trial periods. Although average daily feed intake (ADFI) was not influenced by dietary treatments, increasing Arg up to 100% of NRC recommendations improved (p < .05) feed conversion ratio (FCR) throughout the trial period. Similarly, supplementation of deficient‐diets with Met improved FCR values. There was a significant (p < .01) Arg × Met interaction for ADFI during the starter period; increasing the dietary Arg level increased ADFI when the diets were deficient in Met, while had an opposite effect in diets containing higher dietary Met levels. On the other hand, dietary Met fortification improved (p = .067) FCR values to a greater extent in 110% Arg‐diets during the entire trial period. Although different levels of Arg and Met had no marked effects on carcass yield and abdominal fat percentage, supplemental Arg up to 100% of NRC values increased (p < .01) the relative weights of spleen and bursa of Fabricius. Furthermore, bursa weight was affected by Arg × Met interaction (p < .01), so that supplemental Arg level of 100% of NRC increased the relative bursa weight in birds that were fed diets containing 90% and 110% of Met. Serum uric acid level was decreased (p < .05) as a result of dietary Arg fortification up to 110% of NRC recommended values. Supplementation of deficient‐diets with Met decreased (p < .05) serum cholesterol level. Although Newcastle antibody titer was not affected by dietary Arg or Met levels, Arg fortification of deficient‐diets increased (p < .001) antibody responses against infectious bronchitis (IBV) and bursal (IBD) disease viruses. Similarly, Met supplementation of deficient‐diets increased IBD antibody titer. There were significant (p < .05) Arg × Met interactions for IBV and IBD titers; Met fortification of 110% Arg‐diets was more effective in increasing antibody titers. An increase in dietary Met level up to 100% of NRC values increased (p < .001) serum concentration of γ‐globulins. The present findings imply that supplemental Arg could affect feed efficiency and antibody responses when the diets were already fortified with a sufficient Met level.     

Digestibility,ruminal fermentation,blood metabolites and antioxidant status in ewes supplemented with DL‐methionine or hydroxy‐4 (methylthio) butanoic acid isopropyl ester

The effects of supplementing ewe diets with either DL‐methionine (DL‐Met) or 2‐hydroxy‐4 (methylthio) butanoic acid isopropyl ester (HMBi) were investigated on ruminal in situ degradability of grain and forage diets, in vivo digestibility, rumen fermentation, blood metabolites and antioxidant status. Six ruminally cannulated ewes were used in a replicated 3 × 3 Latin square design with 28‐day periods. The dietary treatments were as follows: (i) no supplemental Met (control; CON), (ii) DL‐Met at 1.2 g/kg DM intake and (iii) HMBi at 1.8 g/kg dry matter (DM) intake. Corn grain, barley grain and alfalfa hay were evaluated for their ruminal degradability by both in situ incubation and effective degradability measurements of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF). Compared to other treatments, HMBi supplementation increased (p < 0.05) the digestibility of organic matter, crude protein and NDF and also tended (p = 0.08) to increase the digestibility of DM and ADF. Moreover, HMBi supplementation increased (p < 0.01) total VFA concentrations, the molar proportions of valerate and iso‐butyrate in the rumen. Compared to the CON treatment, DL‐Met and HMBi treatments tended (p = 0.08) to increase the molar proportion of acetate but decreased (p < 0.05) ruminal ammonia‐N concentration. Ewes supplemented with HMBi and DL‐Met recorded greater (p < 0.05) serum concentrations of glutathione peroxidase, total antioxidant capacity and superoxide dismutase than the CON treatment. Serum concentrations of glucose, total protein, albumin, high‐density lipoprotein and very low‐density lipoprotein were greater (p < 0.01) and serum urea nitrogen (p < 0.05), malonyl dialdehyde and triglyceride were lower (p < 0.02) in the HMBi and DL‐Met animals than in the CON ewes. The results concluded that HMBi is a very effective form of dietary Met supplementation for ewes with a positive effect on digestion, rumen fermentation and serum antioxidant function.     

Effects of supplementation with green tea by‐products on growth performance,meat quality,blood metabolites and immune cell proliferation in goats

Forty‐eight castrated male goats were used to determine the effects of feeding green tea by‐products (GTB) on growth performance, meat quality, blood metabolites and immune cell proliferation. Experimental treatments consisted of basal diets supplemented with four levels of GTB (0%, 0.5%, 1.0% or 2.0%). Four replicate pens were assigned to each treatment with three goats per replicate. Increasing dietary GTB tended to linearly increase the overall average weight gain and feed intake (p = 0.09). Water holding capacity, pH and sensory attributes of meat were not affected by GTB supplementation, while cooking loss was reduced both linearly and quadratically (p < 0.01). The redness (linear; p = 0.02, quadratic; p < 0.01) and yellowness (quadratic; p < 0.01) values of goat meat were improved by GTB supplementation. Increasing dietary GTB quadratically increased protein and decreased crude fat (p < 0.05), while linearly decreased cholesterol (p = 0.03) content of goat meat. The proportions of monounsaturated fatty acid, polyunsaturated fatty acid (PUFA) and n‐6 PUFA increased linearly (p < 0.01) and n‐3 PUFA increased quadratically (p < 0.05) as GTB increased in diets. Increasing dietary GTB linearly increased the PUFA/SFA (saturated fatty acid) and tended to linearly and quadratically increase (p ≤ 0.10) the n‐6/n‐3 ratio. The thiobarbituric acid‐reactive substances values of meat were lower in the 2.0% GTB‐supplemented group in all storage periods (p < 0.05). Dietary GTB linearly decreased plasma glucose and cholesterol (p < 0.01) and quadratically decreased urea nitrogen concentrations (p = 0.001). The growth of spleen cells incubated in concanavalin A and lipopolysaccharides medium increased significantly (p < 0.05) in response to GTB supplementation. Our results suggest that GTB may positively affect the growth performance, meat quality, blood metabolites and immune cell proliferation when supplemented as a feed additive in goat diet.     

Effect of dietary energy on digestibilities,rumen fermentation,urinary purine derivatives and serum metabolites in Tibetan and small‐tailed Han sheep

Tibetan sheep are indigenous to the Qinghai–Tibetan Plateau, graze the grassland all year round without supplementation and are well‐adapted to the harsh conditions. Small‐tailed Han sheep were introduced to the plateau and are raised mainly in feedlots. Based on their different backgrounds, we hypothesized that the ability to cope with poor diets would be better in Tibetan than in Han sheep. To test our prediction, we examined the effect of dietary energy on apparent digestibilities, rumen fermentation, urinary purine derivatives and serum metabolites by using a 4 × 4 Latin square design in each sheep breed. Four diets were formulated to be low in crude protein (~7%) but to differ in metabolizable energy concentration. Average daily gain was greater in Tibetan than in Han sheep (p < 0.01) and increased linearly with an increase in energy intake (p < 0.001). The digestibilities of dry matter, organic matter, gross energy, and neutral and acid detergent fibres were greater in Tibetan than in Han sheep (p < 0.05). Ruminal pH was lower (p < 0.05), while volatile fatty acids (VFAs), urea‐N, ammonia‐N and soluble protein‐N concentrations were higher (p < 0.05) in Tibetan than in Han sheep. As a molar proportion of total VFA, acetate decreased (p < 0.001) with an increase in dietary energy whereas propionate and butyrate increased (p < 0.05). Urinary purine derivative excretion was greater in Tibetan than in Han sheep (p < 0.01), as was microbial nitrogen production; both parameters increased with dietary energy (p < 0.01). Serum concentrations of glucose, insulin and insulin‐like growth factor‐1 increased (p < 0.05) as energy level increased, while non‐esterified fatty acids and growth hormone decreased (p < 0.05). It was concluded that Tibetan sheep were better able to cope with low‐protein, low‐energy diets and, consequently, our prediction was supported.     

The effects of increasing garlic powder and monensin supplementation on feed intake,nutrient digestibility,growth performance and blood parameters of growing calves

The objective of this study was to evaluate the effects of increasing garlic powder and monensin supplementation on feed intake, nutrient digestibility, growth performance and blood metabolites of growing calves. Forty Holstein calves (BW = 100 ± 11 kg) were randomly assigned to four dietary treatments (n = 10) in a complete randomized design. Experimental treatments consisted of the following: (i) basal diet (control), (ii) basal diet supplemented with 0.0003% of dietary dry matter (DM) sodium monensin, (iii) low level of garlic powder (Low‐GAR; 0.5% of dietary DM) and (iv) high level of garlic powder (High‐GAR; 1% of dietary DM). DM intake (DMI) and DM digestibility were (p < 0.05) decreased by High‐GAR. However, calves supplemented with Low‐GAR had a similar DMI to the control calves and similar DM digestibility to the control and monensin groups. The digestibility of other nutrients were not affected by the treatments. Although supplementing monensin relative to Low‐GAR increased the DMI (p < 0.05), average daily gain was similar between Low‐GAR and monensin supplemented calves, which were higher than the control and High‐GAR groups (p < 0.05). As a result, feed conversion ratio was improved in the Low‐GAR group versus other treatment groups (p < 0.05). Administrating garlic powder decreased the blood low‐density lipoprotein (LDL) and non‐esterified fatty acids (p < 0.05) without affecting the blood triglyceride, high‐density lipoprotein and beta‐hydroxybutyric acid concentrations. In conclusion, the calves fed the Low‐GAR showed an improved FCR and blood metabolites without changing the DMI and nutrient digestibility. It suggests that garlic powder could be used as an alternative to monensin for growing calves under the current feeding conditions.