The effects of different dietary amounts of organic and inorganic Zn were studied in male White Pekin ducks (WPD) from 1 to 56 days of age. The control diet (26 ppm of Zn from raw ingredients) was ...supplemented with 30, 60 and 120 ppm of Zn from both inorganic and organic sources, for a total of seven treatment groups, each containing five replicates of nine 1-day-old ducklings each. BW, feed intake and feed conversion ratio (FCR) were recorded at 1, 28 and 56 days of age. At 56 days of age, five birds per group were used in a digestibility trial to measure Zn retention and excretion. At the end of the trial, five birds per treatment were slaughtered and carcass traits as well as Zn content in tibia and liver were measured. Samples of blood from five birds per treatment were used to measure plasma concentration of Zn and Cu. BW gain during the entire period of the trial increased (P < 0.001) by 30 and 60 ppm of Zn. Increasing Zn contents progressively increased (P < 0.001) the tibia and the liver Zn contents as well as the plasma Zn and Cu contents. The concentration of 120 ppm of Zn increased (P < 0.001) tibia ash and decreased (P < 0.001) abdominal fat in the carcasses. In the period 1 to 56 days, Zn oxide increased (P < 0.001) growth rate and improved (P < 0.03) FCR compared with organic Zn, whereas organic Zn increased (P < 0.003) the dressed carcass percentage. Organic Zinc increased (P < 0.001) Zn and Cu concentration in the plasma. A level of 30 ppm of Zn from an inorganic source was adequate for male WPD during 1 to 56 days of age, based on positive effects of growth rate and Zn excretion.
Octacosanol, which has prominent physiological activities and functions, has been recognized as a potential growth promoter in animals. A total of 392 1-d-old male Arbor Acres broiler chicks with ...similar body weight were randomly distributed into four dietary groups of seven replicates with 14 birds each supplemented with 0, 12, 24, or 36 mg octacosanol (extracted from rice bran, purity >92%)/kg feed. The feeding trial lasted for six weeks and was divided into the starter (day 1 to 21) and the grower (day 22 to 42) phases. The results showed that the feed conversion ratio (FCR) was significantly improved in broilers fed a diet containing 24 mg/kg octacosanol compared with those fed the control diet in the overall phase (day 1 to 42, p = 0.042). The average daily gain and FCR both showed linear effects in response to dietary supplementation of octacosanol during the overall phase (p = 0.031 and 0.018, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet showed a higher eviscerated yield, which increased by 5.88% and 4.26% respectively, than those fed the control diet (p = 0.030). The breast muscle yield of broilers fed with 24 mg/kg octacosanol diet increased significantly by 12.15% compared with those fed the control diet (p = 0.047). Eviscerated and breast muscle yield increased linearly with the increase in dietary octacosanol supplementation (p = 0.013 and 0.021, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet had a greater (p = 0.021) pH45min value in the breast muscle, which was maintained linearly in response to dietary octacosanol supplementation (p = 0.003). There was a significant decrease (p = 0.007) in drip loss value between the octacosanol-added and the control groups. The drip loss showed linear (p = 0.004) and quadratic (p = 0.041) responses with dietary supplementation of octacosanol. These studies indicate that octacosanol is a potentially effective and safe feed additive which may improve feed efficiency and meat quality, and increase eviscerated and breast muscle yield, in broiler chicks. Dietary supplementation of octacosanol at 24 mg/kg diet is regarded as the recommended dosage in the broilers' diet.
The effects of low-protein (LP) diets and rumen-protected CLA on DMI, ADG, carcass traits, and health status of double-muscled Piemontese young bulls were investigated. Forty-eight bull calves (BW = ...237 ± 24 kg) were divided in 4 groups and housed in 12 fully slatted pens. Bulls were fed 2 diets differing in CP density high-protein (HP) diet: CP = 145 g/kg of DM; LP diet: CP = 108 g/kg of DM and top-dressed with 80 g/d of rumen-protected CLA or 65 g/d of hydrogenated soybean oil. Orts were collected weekly and feed intake was estimated on a pen basis, with 3 replicated pens for each treatment. Each bull was weighed monthly and examined for alterations of the locomotion system by using the locomotion score as an index of lameness and by counting the number of swollen joints. Carcass quality traits were measured at slaughter, after a feeding period of 332 d. Compared with HP, LP reduced ADG only during the first 4 mo of the trial (1.30 vs. 1.53 kg/d, P = 0.003). However, because of compensatory growth, over the whole trial, no significant effects attributable to CP or to additive were found on final BW (668 kg), ADG (1.19 kg/d), DMI (8.50 or 86 g/d per kg of BW⁰.⁷⁵), dressing percentage (67.3%), carcass conformation (5.2 points), and carcass fat covering (1.87 points). Feed efficiency was affected by a CP x additive interaction (P = 0.030), with CLA improving feed efficiency when added to the LP diets, whereas feed efficiency was reduced with the HP diets. The addition of both LP and CLA reduced the number of bulls presenting swollen joints (P = 0.001), and LP improved the locomotion score (P = 0.021) compared with HP. It was concluded that 10.8 g/kg of CP density in the diet is sufficient for double-muscled Piemontese bulls. The reduction in CP density from 145 to 108 g/kg of DM, in addition to reducing the feeding cost, allows a strong reduction in N consumption without negative consequences on growth performance and carcass traits.
The effects of an extract of the brown seaweed
Ascophyllum nodosum (AN) in grower–finisher pigs are reported. In Experiment 1, the effect of dietary supplementation with increasing levels of AN ...extract (ANE) on growth performance, carcass characteristics and gastrointestinal microflora was investigated. A total of 360 pigs were randomly allocated, based on initial live-weight and sex, to one of four experimental treatments as follows; control diet (no ANE), control diet plus 3
g
ANE/kg, control diet plus 6
g
ANE/kg and control diet plus 9
g
ANE/kg. These diets were fed
ad libitum up to slaughter. In Experiment 2, eight male pigs were allocated to a control diet (no ANE) or the control diet plus 2.5
g ANE/kg to determine effects of ANE on coefficient of total tract apparent digestibility (CTTAD) of nutrients and nitrogen (N) balance. Supplementation with increasing levels of ANE in Experiment 1 resulted in reduced daily gain, carcass weight and kill-out yield during the combined grower–finisher period (P<0.05); however, there were no effects of treatment on feed intake, feed conversion ratio or carcass characteristics. Increasing levels of dietary ANE resulted in decreased ileal coliform counts (P<0.05). Increasing dietary ANE also tended to increase adherent lactobacilli in the colon (P=0.080) but caecal bifidobacteria declined (P<0.05). There were trends towards a linear reduction in colonic bifidobacteria (P=0.077) and towards a quadratic effect on rectal lactobacilli (P=0.077). Intestinal pH was unaffected by ANE supplementation (P>0.05). In Experiment 2, the CTTAD was unaffected by the inclusion of ANE (P>0.05). Overall, the intestinal coliform reductions obtained suggest that ANE may provide a dietary means to improve gut health and potentially reduce pathogen carriage in finishing pigs. However, the negative effects on growth performance observed in healthy animals will most likely limit the commercial use of dietary ANE as a feed additive.
A six-week trial was conducted to determine the effect of lowering dietary crude protein levels with supplementation of limiting amino acid on growth performance, and carcass characteristics in one ...of the Indian improved crossbred Swarnadhara chicks in a completely randomized design having five treatments and four replications of 20 birds in each. Five isocaloric (2800 ME Kcal//kg) experimental diets based on corn-soy bean meal were formulated in a gradual crude protein decline from 21 % (control T1) to 19% by 0.5% interval. The levels of limiting amino acids namely methionine, lysine, threonine and tryptophan were met as that of control (T1) by adding synthetic preparations. Highest body weight was recorded in 2% crude protein reduced group (T5) which was comparable with control (T1). However, cumulative feed intake and feed conversion ratio of different treatments were not significantly different. Moreover, carcass parameters like dressing percentage, breast meat yield, liver and heart weights remained unaffected by the dietary treatments. Relative gizzard weight and abdominal fat weights showed variations and lower dietary protein diets were comparable with control diet (T1). In summary, crude protein content of Swarnadhara chick diet can be reduced to 19% with essential AA fortification without any adverse effect on growth performance and carcass characteristics during 0-6 weeks of age.
Ninety-three crossbred steer calves (BW ± SD = 385 ± 50 kg) were used (n = 48 steers in yr 1, n = 45 steers in yr 2) to examine the relationship among carcass traits, lean, bone, and fat proportions, ...visceral tissue weights, and pancreatic digestive enzyme activity with DMI, ADG, G:F, and residual feed intake. Calves were progeny from crossbred dams predominantly of Angus and Simmental breeding and were sired by Angus, Simmental, crossbred (predominantly of Angus and Simmental breeding), Charolais, or Piedmontese bulls. Steers were fed a high-moisture corn-based diet for an average of 112 d. Partial correlation analysis accounting for year, pen within year, week of slaughter within year, and sire breed was conducted. Gain:feed was negatively correlated (P less-than or equal to 0.04) with backfat thickness (r = -0.38), marbling score (r = -0.32), and trim and kidney fat weight proportion (g/kg of BW; r = -0.42). Residual feed intake (P = 0.008; g/kg of BW; r = 0.34) and backfat-corrected residual feed intake (P = 0.005; r = 0.29) were positively correlated with trim and kidney fat weight proportion. Gain:feed was negatively correlated (P < 0.001) with total fat weight proportion (g/kg of rib; r = -0.45) and positively correlated (P less-than or equal to 0.03) with lean weight proportion (g/kg of rib; r = 0.30) and bone weight proportion (g/kg of rib; r = 0.28). Gain:feed was negatively correlated (P less-than or equal to 0.01) with subcutaneous fat weight proportion (g/kg of rib; r = -0.32) and intramuscular fat weight proportion (g/ kg of rib; r = 0.37). Gain:feed was negatively correlated (P < 0.001) with total visceral weight proportion (g/kg of BW; r = -0.44) and visceral fat weight proportion (g/kg of BW; r = -0.41) but was positively correlated (P = 0.02) with spleen weight proportion (g/kg of BW; r = 0.30). There were no significant correlations (P > 0.10) between performance measures and the pancreatic proportional content of α-amylase and trypsin activity (units/kg of BW). These data indicate that carcass fatness traits and changes in the proportional weight of total viscera may be negatively associated with G:F and that visceral fat weight proportion and trim and kidney fat weight proportion may be important factors influencing this relationship.
Tail biting is a common welfare problem in pig production and in addition to being a sign of underlying welfare problems, tail biting reduces welfare in itself. The aim of this study was to evaluate ...the effects of tail biting on different pre and post mortem indicators of stress in slaughter pigs and on carcass and meat characteristics. A total of 12 tail bitten (TB) and 13 control (C) pigs from a farm with a long-term tail biting problem were selected for salivary cortisol analyses before and after transport to the slaughterhouse. After stunning, samples were taken for the analysis of serum cortisol, blood lactate, intestinal heat shock protein 70 (HSP70), and meat quality characteristics. In addition, body temperature immediately after and muscle temperature 35 min after stunning were measured, as well as lean meat percentage and carcass weight.
TB pigs showed a lower cortisol response to the transport-induced stress than C pigs and also had a lower serum cortisol concentration after stunning. HSP70 content in the small intestine was higher in the TB pigs than in C pigs. TB pigs had a considerably lower carcass weight therefore produced a lower total amount of lean meat per carcass than C pigs.
This study suggests that prolonged or repeated stress in the form of tail biting causes a blunted stress response, possibly a sign of hypocortisolism. In addition, it underlines the importance of reducing tail biting, both from an animal welfare and an economic point-of-view.
As a new modeling method, support vector regression (SVR) has been regarded as the state-of-the-art technique for regression and approximation. In this study, the SVR models had been introduced and ...developed to predict body and carcass-related characteristics of 2 strains of broiler chicken. To evaluate the prediction ability of SVR models, we compared their performance with that of neural network (NN) models. Evaluation of the prediction accuracy of models was based on the R(2), MS error, and bias. The variables of interest as model output were BW, empty BW, carcass, breast, drumstick, thigh, and wing weight in 2 strains of Ross and Cobb chickens based on intake dietary nutrients, including ME (kcal/bird per week), CP, TSAA, and Lys, all as grams per bird per week. A data set composed of 64 measurements taken from each strain were used for this analysis, where 44 data lines were used for model training, whereas the remaining 20 lines were used to test the created models. The results of this study revealed that it is possible to satisfactorily estimate the BW and carcass parts of the broiler chickens via their dietary nutrient intake. Through statistical criteria used to evaluate the performance of the SVR and NN models, the overall results demonstrate that the discussed models can be effective for accurate prediction of the body and carcass-related characteristics investigated here. However, the SVR method achieved better accuracy and generalization than the NN method. This indicates that the new data mining technique (SVR model) can be used as an alternative modeling tool for NN models. However, further reevaluation of this algorithm in the future is suggested.
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