Effects of autografting ovarian tissue,ovariectomy and implanting on growth rate and carcass characteristics of feedlot heifers

Ninety heifers sired by Charolais or Red Poll bulls were utilised in two trials involving ovariectomy, ovarian tissue transplants (autografts) andlor an anabolic implant. In trial 1, four treatments were imposed upon 60 heifers: (1) autograft, (2) autograft plus Synovex-H® implant, (3) vaginal ovariectomy plus implant, and (4) intact plus implant. Three replications of five heifers per treatment were fed a finishing diet until heifers weighed approximately 432 kg. Autografed-implanted heifers exhibited a greater average daily gain than non-implanted autografted heifers (P < 0.05). No treatment effects were detected for feed eficiency or dressing percentage. Carcasses from autografted heifers merited higher marbling scores and USDA quality grades than did those of ovariectomised-implanted heifers. Fat thickness tended to be greater for autografted heifers than for heifers in the implant treatment groups (P <0.l0). Non-implanted autografted heifers had smaller ribeye areas, more kidney, pelvic and heart fat, and higher numerical USDA yield grades. Shear force values and taste panel scores for meat favoured non-implanted autografted heifers. In trial 2, 30 heifers were autografted, ovariectomised via high lumbar laparotomy, or left as intact controls. Heifers in trial 2 were fed a finishing diet until heifers reached 1.2 ern average backfat thickness. Intact heifers tended to gain weight more rapidly than did ovariectomised heifers. Ovarian cell types were detected at the graft sites of only four of the 10 autografted heifers upon post-mortem histological examination. Very low levels of oestrogen were present in the fluid aspirated from three of the apparently successful grafts. However, growth rate was not superior for these three heifers.     

Chromium picolinate can ameliorate the negative effects of heat stress and enhance performance,carcass and meat traits in broiler chickens by reducing the circulatory cortisol level

BACKGROUND: Dietary chromium (Cr³⁺) supplementation reduces stress in livestock by lowering circulatory cortisol and potentiating the action of insulin. This study aimed to assess the stress‐alleviating effects of supplemental Cr³⁺ as chromium picolinate in broilers. RESULTS: The birds, which were heat stressed and had restricted feed intake between 31 and 40 days of age, were supplemented with 0 (control), 0.5 or 1 mg Cr³⁺ kg^?1 diet from 10 to 40 days of age. Live weight gain, feed efficiency, utilisation efficiency of energy and protein and conversion efficiency of feed protein to muscle protein improved owing to Cr³⁺ supplementation (P < 0.05), especially during the period of feed restriction. Cr³⁺ supplementation increased hot and eviscerated carcass weights and breast weight (P < 0.05) and reduced ether extract content (P = 0.02, linear effect). Meat protein accretion improved owing to Cr³⁺ supplementation (P = 0.006, quadratic effect). Relative to its pre‐supplementation value, serum cortisol increased by 2.3% in the control group and decreased by 7.6 and 14.3% in the 0.5 and 1 mg Cr³⁺‐supplemented birds respectively (age × diet interaction P = 0.0001). CONCLUSION: It was concluded that supplemental Cr³⁺ may ameliorate heat stress and augment growth in broilers during periods of physical feed restriction. However, increasing the inclusion of Cr³⁺ beyond the dose level of 0.5 mg kg^?1 diet may not be substantially beneficial. Copyright © 2007 Society of Chemical Industry     

Growth performance,nutrient digestibility and immune response of broiler chicks fed diets supplemented with a culture of Lactobacillus bulgaricus

BACKGROUND: Probiotics are being developed for use in animal feed to enhance production performance and prevention of gastrointestinal infections. The ban on using antibiotics as growth promoters, antibiotic resistance and the inherent problems of developing new vaccines make a compelling case for developing alternatives for in‐feed antibiotics. The alternatives of choice have to be considered under the environmental conditions of the animal. Among the probiotics in use today, Lactobacillus has been shown to play a vital role in disease prevention, immune enhancement, improved growth and carcass yield in poultry. The present study investigates the effect of Lactobacillus bulgaricus (LB)‐based probiotic on the growth performance, nutrient digestibility and immune response of broilers under tropical environmental conditions. RESULTS: Broilers fed LB diets consumed more feed (P < 0.05) and had greater body weight gain than the control group. Feed/gain ratio improved significantly (P < 0.05) with the 20, 40 and 60 mg kg^?1 LB diets compared with the control or 80 mg kg^?1 LB diet. The apparent digestibilities of nitrogen and fat increased with LB supplementation. However, there was no significant difference (P > 0.05) in fibre digestibility. White blood cell count increased significantly in broilers fed higher levels (>40 mg kg^?1) of LB compared with the control group. Antibody production measured as antibody titre against Newcastle disease vaccine showed a curvilinear response over the range of LB concentrations examined. CONCLUSION: The results indicate that LB addition to broiler chick diets significantly improved growth performance, increased nutrient digestibility and stimulated humoral immune response. Copyright © 2008 Society of Chemical Industry     

Low‐protein amino acid‐supplemented diets in broiler chickens: effects on performance,carcass characteristics,whole‐body composition and efficiencies of nutrient utilisation

Two concurrent trials were conducted to investigate the influence of low‐protein amino acid‐supplemented diets on the performance, carcass characteristics, whole‐body composition and efficiencies of nutrient utilisation by the male broiler chicken from age 3 to 6 weeks. The first trial comprised five isoenergetic (13.0 MJ kg⁻¹) diets containing 225 (control), 210, 190, 172 or 153 g kg⁻¹ crude protein (CP) supplemented with essential amino acids (EAAs) to meet the minimum National Research Council recommendations. In the second trial a composite mixture of non‐essential amino acids (NEAAs) was added to the lower‐CP diets (ie 210–153 g kg⁻¹) such that they became isoproteinous (N × 6.25) with the 225 g kg⁻¹ control. Neither the lowering of dietary CP nor NEAA supplementation had any significant influence on weight gain or the relative weights of the various carcass cuts. However, chicks fed the lowest‐CP diets consumed more feed (P ≤ 0.05) and had poorer (P ≤ 0.05) feed conversion efficiency (FCE). NEAA supplementation enhanced FCE to the control levels. Whole‐body compositional analysis showed that lowering dietary CP increased (P ≤ 0.01) total body fat in a linear fashion (P ≤ 0.001; r = −0.72). Equalising dietary CP with the control (ie maintaining identical energy/protein ratio) by NEAA supplementation did not correct for the fat deposition. Total body protein (g kg⁻¹) was identical with the control with or without NEAA supplementation. Dietary energy, protein retention efficiency (PRE) and protein efficiency ratio (PER) were more efficient (P ≤ 0.01) in the lower‐protein diets, while NEAA supplementation significantly (P ≤ 0.01) decreased the efficiency of N utilisation. Reducing dietary CP from 225 to 153 g kg⁻¹ decreased N excretion in a highly significant linear fashion (P ≤ 0.001; r = 0.73). The nutritional and environmental implications of the increased body fat deposition on the one hand and the decreased N excretion on the other in the low‐protein‐fed chickens are discussed and the need to harmonise these apparently conflicting interests is emphasised. © 2000 Society of Chemical Industry     

Effects of genotype, level of supplementation, and organic chromium on growth performance, carcass, and meat traits grazing lambs

The aim of the present study was to evaluate the effects of Suffolk×Dorper (SD) and Rambouillet (R) lamb genotypes, dietary supplementation, and organic chromium on growth performance, carcass, and meat traits in male lambs grazing ryegrass pasture. SD lambs had heavier cold carcass (HCW) and better carcass yield (CY) and rib eye area at 12th rib (RA) than R lambs; R had larger legs. Feed supplement increased average daily weight gain (ADG), slaughter live weight (SLW), hot carcass weight (HCW) and cold carcass weight (CCW), carcass yield, carcass length (CL), leg perimeter (LP), major thorax width (MTW), minor thorax width (MiTW), rib eye area and dorsal fat at 12th rib (DF12), and also decreased meat moisture. Organic chromium reduced dorsal fat at 12th rib and meat fat content.     

载锌沸石对肉鸡生产性能、抗氧化功能及其相关基因表达的影响

研究载锌沸石(Zn CP,锌含量为15.5 mg/g)对肉鸡生产性能、肝脏锌沉积、抗氧化功能及其相关基因表达的影响,探讨Zn CP作为抗生素替代品的可行性。300只1日龄AA(Arbor Acres)肉鸡随机分成5组,每组6个重复,每个重复10只鸡,试验期为42 d。试验日粮:1)对照组,基础日粮(含Zn SO4,锌含量为60mg/kg);2)基础日粮+抗生素(40 mg/kg金霉素);3)基础日粮+0.1%Zn CP;4)基础日粮+0.2%Zn CP;5)基础日粮+0.4%Zn CP。结果表明,与对照组相比,不同剂量Zn CP显著提高肉鸡前期体增重(P0.05),0.1%和0.2%的Zn CP显著提高21 d肝脏T-SOD和Cu Zn-SOD的活性(P0.05),0.2%的Zn CP显著降低21 d肝脏MDA含量(P0.05),抗生素组和Zn CP组均能显著提高21 d肝脏T-AOC(P0.05);与抗生素组相比,0.1%和0.2%的Zn CP显著降低21 d肝脏MDA含量(P0.05),显著提高21 d肝脏T-SOD的活性(P0.05),0.1%的Zn CP显著提高42 d肉鸡肝脏Nrf2 mRNA的相对表达量(P0.05)。与对照组和抗生素组相比,0.2%的Zn CP显著降低42 d肉鸡肝脏MDA含量(P0.05)。结果提示,肉鸡日粮中添加Zn CP能提高生产性能,效果等同或优于抗生素;Zn CP可能通过提高Keap1/Nrf2/ARE/抗氧化酶信号通路关键基因Nrf2的表达量来提高肉鸡的抗氧化能力;本试验条件下,日粮中Zn CP以0.1%和0.2%的添加量较好。     

Effects of dietary supplementation of cysteamine on growth performance,carcass quality,serum hormones and gastric ulcer in finishing pigs

A study was conducted to determine the effects of graded levels of dietary inclusion of a cysteamine (Cs) preparation on growth performance, carcass quality, plasma hormone levels, gastric pH and occurrence of gastric ulcer in finishing pigs. A total of 384 Landrace × Large White finishing pigs, (192 gilts and 192 barrows) with an average initial body weight of 66.05 ± 0.623 kg (mean ± SEM) were randomly divided into 24 floor pens, with eight gilts and eight barrows in each pen (9.2 m²) as one experimental unit. The 24 pens of pigs were randomly allocated to one of three diets: (1) a maize/soybean meal basal diet; (2) the basal diet plus 30 mg Cs kg^?1 diet; and (3) the basal diet plus 50 mg Cs kg^?1 diet. Dietary supplementation of Cs had quadratic effects (P < 0.01) on final body weight and average daily gain, with optimal responses occurring at 30 mg kg^?1. Dietary supplementation of Cs quadratically improved (P < 0.01) average daily feed intake and feed/gain ratio, with optimal responses occurring at 30 mg kg^?1. Dietary supplementation of Cs had a quadratic effect (P < 0.01) on muscle RNA/DNA ratio. Furthermore, dietary supplementation of Cs reduced (P < 0.05) back‐fat thickness. Dietary supplementation of Cs had quadratic effects (P < 0.05) on plasma glucagon and T₃ hormone levels, with optimal responses occurring at 30 mg kg^?1, but had no effect (P > 0.05) on plasma growth hormone, insulin and T₄ levels. There were no apparent pathological changes seen in the stomach mucosa of pigs fed at 30 mg Cs kg^?1 compared with the control diet. It is concluded that a low dose of dietary inclusion of Cs at 30 mg kg^?1 can improve growth performance and carcass quality without adverse effects on the stomach in finishing pigs. Copyright © 2005 Society of Chemical Industry     

Effects of dietary humate supplementation to broilers on performance,slaughter, carcass and meat colour

BACKGROUND: This experiment was designed to examine the effect of dietary humate supplementation primarily on pH and colour parameters of carcasses, breast fillets and drumsticks and, secondarily on performance and carcass characteristics in broilers. RESULTS: A total of 240 male broiler chicks (Ross‐308) were randomly allocated to four dietary treatments varying in supplemental humate level (0, 0.1, 0.2 and 0.3% for H₀, H₁, H₂ and H₃). Dietary humate supplementation did not affect performance traits and slaughter, hot carcass weights and yields. Carcass‐related variables (pH, L*, a*, b*, H* and C*) were responsive to the dietary treatments. The L*, a*, b*, and C* values for drumstick muscles were higher than those for breast muscles. Except for the L* value, meat colour parameters changed due to packaging. The a* value was higher and b* value was lower for vacuum packaged breast and drumsticks than for those aerobic packaged. Storage period affected colour parameters; while L*, b*, H* and C* values were higher for drumstick skin than for drumstick meat; the a* value was greater in drumstick meat than in skin. CONCLUSION: pH and colour parameters of carcasses, breast fillets and drumsticks of broilers were improved by dietary humate supplementation. However, responses of broiler performance and slaughter and carcass characteristics were minimal. Copyright © 2008 Society of Chemical Industry     

Effect of dietary sorghum germ meal on performance and meat quality of broiler chicks

Two hundred Lohmann broiler chicks were equally allocated into 20 pens after being adapted on a control diet for 7 days. The four dietary treatments containing graded levels of sorghum germ meal (SGM, 0, 75, 150, 225 g kg^?1) were randomly assigned to the pens (five pens per dietary treatment). L-Lysine and DL-methionine were added to the diets to raise their contents to the recommended levels for starter broiler chicks. Feed and water were provided ad libitum throughout the 6-week experimental period. The dietary treatment had negative linear effects (P < 0.01) on body weight, feed intake, weight gain, feed:gain ratio and dressing percentage, and a positive linear effect (P < 0.01) on liver and viscera relative weights. It had insignificant effects (P > 0.05) on pancreas, bursa relative weights, incidence of leg abnormalities and mortality rate. Abdominal fat relative weight had shown a significant negative linear effect (P < 0.05). Dietary SGM had no detectably different effect on colour, juiciness, tenderness and flavour of the meat when evaluated by semi-trained panellists.     

Effect of diatomaceous earth on the performance and blood variables of broiler chicks during experimental aflatoxicosis

BACKGROUND: Diatomaceous earth (DE) is a type of tectosilicate found in large quantities in Iran. It is possible that this compound can absorb mycotoxins. An experiment was conducted to evaluate the protective effects of DE on experimental aflatoxicosis in broilers from 1 to 42 days of age. In four treatments of four replicates, 160 one‐day‐old Hubbard male chicks were subjected to two levels of aflatoxin B₁ (AFB₁) (0 and 1.0 mg kg^?1) and DE (0 and 30 mg kg^?1) RESULTS: Body weight gain, feed intake, feed conversion ratio, and productive efficiency index were adversely affected in the chicks treated with AFB₁. Weight of heart was significantly decreased (20.3%) by AFB₁ (P < 0.05). Serum total protein, albumin, and the activity of serum lactate dehydrogenase (LDH) were decreased by AFB₁. DE significantly (P < 0.05) increased body weight gain (9.51%), feed intake (7.44%), and improved feed conversion ratio (2.08%) as well as productive efficiency index (5.48%) in the birds that subjected to AFB₁ DE also increased serum albumin (22.6%), and the activity of serum LDH (44.4%). CONCLUSION: DE might be beneficial in reducing toxic effects of AFB₁ in broilers. It is possible to include DE as an alternative to other mycotoxin binders at levels of 30 mg kg^?1 in the diets on offer to broilers between the ages of 1 and 42 days. Copyright © 2007 Society of Chemical Industry     

Pig sire type and sex effects on carcass traits,meat quality and physicochemical and sensory characteristics of Serrano dry‐cured ham

This study demonstrates that improvements in animal line selection by breeding enterprises exert a strong effect on carcass traits, meat quality and sensory characteristics of Serrano dry‐cured ham. A total of 461 pigs from the offspring of a Duroc (DU) × Landrace (LD) sow mated with two DU boars and a DU × Large White (LW) boar from three breeding enterprises were evaluated. The two DU terminal sires were significantly different (P < 0.05) in carcass conformation, backfat thickness, ham and loin yields, raw ham traits, myoglobin concentration and total pigments formed during the curing process; in addition, the two lines provided different percentages of hams (54 vs 91%) with sufficient subcutaneous fat and weight to manufacture dry‐cured Serrano hams using a slow ripening process (11 months). The DU × LW sire had the best carcass and ham traits from an economic standpoint and obtained highest scores for sensory characteristics of Serrano ham evaluated by a trained panel test; furthermore, this line provided 84% of total hams suitable for manufacturing Serrano hams by a slow process. When the sex effect was analysed, carcass and ham traits of females were more favourable, but females presented a higher incidence of pale, soft and exudative (PSE) meat and a lower percentage of hams with sufficient subcutaneous fat and weight to produce Serrano hams using a slow ripening process (61% for females and 91% for castrates). On the other hand, castrates provided Serrano hams cured by a slow procedure with better organoleptic characteristics than females. Right and left hams were similar. Copyright © 2005 Society of Chemical Industry     

Effect of increasing energy and protein intake on body growth and carcass composition of heifer calves

The objective was to determine whether increased energy and protein intake between 2 and 14 wk of age would increase growth rates of heifer calves without fattening. At 2 wk of age, Holstein heifer calves were assigned to 1 of 4 treatments in a 2 x 2 factorial arrangement with 2 levels of protein and energy intake (moderate [M]; high [H]) in period 1 (2 to 8 wk of age) by 2 levels of protein and energy intake (low [L]; high [H]) in period 2 (8 to 14 wk of age) to produce similar initial BW for all 4 treatments. Treatments were ML, MH, HL, and HH, indicating moderate or high energy and protein intake during the first period and low or high intake during the second period. The M diet consisted of a standard milk replacer (21.3% CP, 21.3% fat) fed at 1.1% of BW on a DM basis and a 16.5% CP grain mix fed at restricted intake to promote 400 g of average daily gain (ADG), whereas the L diet consisted only of the grain mix. The H diet consisted of a high-protein milk replacer (30.3% CP, 15.9% fat) fed at 2% of BW on a DM basis and a 21.3% CP grain mix available ad libitum. Calves were weaned gradually from milk replacer by 7 wk and slaughtered at 8 (n = 11) or 14 wk of age (n = 41). In periods 1 and 2, ADG and the gain:feed ratio were greater for calves fed the H diet. Calves fed the H diet were taller after both periods 1 and 2. No difference was observed in carcass composition at 8 wk, but at 14 wk calves fed MH and HH had less water and more fat than calves fed ML and HL. Plasma IGF-I concentrations were greatest for calves fed the H diet during either period. Plasma leptin concentrations were increased in calves fed the H diet during period 1 from 4 to 6 wk of age. Increasing energy and protein intake from 2 to 8 wk and 8 to 14 wk of age increased BW, withers height, and gain:feed ratio. Calves fed the H diet from 8 to 14 wk of age had more body fat than calves fed the L diet. Increased energy and protein intake can increase the rate of body growth of heifer calves and potentially reduce rearing costs.     

Intestinal function and body growth of broiler chickens on maize‐based diets supplemented with mimosa tannins and a microbial enzyme

A study was conducted to evaluate the effects of tannin (0, 5, 15, 20 and 25 g kg^?1 diet) and a microbial enzyme supplement (MES) on the feed consumption, body growth and digestive physiology of broiler chickens between hatch and 22 days of age. Feed intake, body weight and body weight gain declined (p < 0.001) with an increase in dietary tannin content. Feed conversion efficiency was increased (p < 0.001) in line with dietary tannin level, up to 15 g kg^?1 diet. There were no significant effects of dietary treatment on the protein content of pancreatic tissue or activities of pancreatic and jejunal enzymes. The ileal digestibilities of energy, protein, arginine, alanine and leucine were reduced (p < 0.001) as dietary tannin level rose to 20 g kg^?1 diet and beyond. The digestibilities of methionine and phenylalanine were also negatively affected (p < 0.01) at the highest level of dietary tannins, while phosphorus digestion was improved (p < 0.05) on diets containing tannin. Apart from an increase (p < 0.01) in the protein content of the jejunal mucosa of birds on the diet with 20 g tannin kg^?1 diet, there were no significant effects of the MES on most of the variables assessed. The results demonstrate the negative effects of tannin, especially at high levels of inclusion in the diet. However, neither tannins nor MES influenced the activities of digestive enzymes assessed, suggesting that a wider range of factors may be involved in regulating the effects of tannins on poultry. Copyright © 2004 Society of Chemical Industry