2. Storage of uneviscerated Wrolstad turkeys at 4 °C for 10 days caused no statistically significant changes in meat flavour or texture.
3. During further storage at —2 °C, however, there was a slight but significant change in flavour, which became more marked with time in birds which had been eviscerated after the initial period at 4 °C.
4. Both eviscerated and uneviscerated birds became slightly tougher during storage.
5. Initial holding at 4 °C increased the numbers of psychrotrophic bacteria on the skin by about 103 but subsequent changes at — 2 °C were slight for uneviscerated birds.
6. Eviscerated carcases had higher counts than uneviscerated birds after storage at — 2 °C and, although ‘off’ odours were not detected, spoilage appeared to be imminent at the end of the 20‐d period. 相似文献
2. The positive effect of a high CP diet on body weight was significant only for the first 4 weeks after hatching.
3. The mean age at inflection point of the growth curve (t +) across lines and sexes was 1.4 d (0.6 to 2.8 d within line/sex groups) earlier for quail fed on a high CP diet than in quail receiving a low CP diet. The inflection (y +) and asymptotic (A) weights were similar under both dietary protein concentrations. Nevertheless, the shape of the growth curve, characterised by the ratio y+1A and parameter of the maturing rate k, was significantly influenced by diet.
4. A higher food intake and less efficient food conversion were found for quail fed on a high CP diet in the period from 15 to 28 d of age.
5. The fattening traits such as body weight, cumulative food intake and food conversion, were not affected by dietary CP content at the age of 5 weeks.
6. The effects of line on body weight, food intake and food conversion are discussed. 相似文献
2. A total of 375 day-of-hatch mixed sex ROSS 308 broilers (BW of 46 ± 0.1 g) were used in a 5-week experiment and randomly allotted to one of the following dietary treatments: (1) NC, basal diet; (2) PC, basal diet + 40 mg/kg of avilamycin; (3) B, NC + 0.1% β-glucan; (4) K, NC + 0.1% kefir; (5) BK, NC + 0.1% β-glucan + 0.1% kefir.
3. During weeks 0–3, broilers in B, K and BK treatments had higher body weight gain (BWG) than those in NC treatment. During weeks 4–5, BK treatment had a higher BWG than NC treatment. Overall, broilers given PC, K and BK diets had higher BWG than those given NC diet. The feed efficiency ratio (FCR) was improved by PC treatment.
4. Relative liver weight was increased by B treatment, whereas the relative weight of breast meat and gizzard was higher in BK group than that in NC group. Broilers given PC, B and BK diets had greater breast meat redness value and reduced drip loss at d 5 and d 7. The cooking loss was also reduced by B and BK treatments compared with NC treatment.
5. In conclusion, the results suggested that inclusion of 0.1% β-glucan and 0.1% kefir, either individually or combined, would improve growth performance and benefit meat quality in broiler chickens. 相似文献
2. Growth virtually ceased after feeding ethionine for 2 d.
3. Ethionine induced an accumulation of lipid, decreased the activities of malic enzyme and isocitrate dehydrogenase and increased the activity of lactate dehydrogenase.
4. The concentration of glycogen in the liver of ethionine‐fed chickens increased for 3 d in spite of a decrease in food intake, but then decreased. 相似文献
2. Doubling the D3 supplement in the control diet (27.5 μg or 1100 IU/kg) almost linearly increased the circulating concentration of 25‐OH‐D3 without raising the concentration of calcitriol, Ca, or egg SG.
3. Replacing D3 by the optimal concentration of calcitriol (5 μg/kg diet) improved egg SG after 21 weeks of treatment without increasing blood calcitriol or total Ca.
4. By itself, 24,25‐dihydroxycholecalciferol [24,25‐(OH)2D3] was unable to maintain normal blood levels of calcitriol, Ca or egg SG and, when added together with calcitriol in the diet, tended to elevate blood Ca but suppress the beneficial effect of calcitriol on shell quality, with little or no effect on blood calcitriol. 相似文献
2. The pelleting degrees (PDs) were as follows: 0 mash; 0·5 mixture of soft pellets and mash 1 to 1; 1 soft pellets pelleted once; 1·5 mixture of soft and hard pellets 1 to 1; 2 hard pellets pelleted twice.
3. In experiment 2, the weight and length of the digestive organs were determined as well as digestive enzyme activities. In both experiments, the behaviour recorded was eating, standing, sitting and drinking.
4. Food intake and body weight gain were related to the degree of pelleting in a curvilinear manner. PD had a positive effect up to a peak (1 to 1·5 PD), after which its effect decreased. Food efficiency was not related to PD. In experiment 1, food efficiency of PDs 1 to 2 were superior to PDs 0 to 0·5 and in experiment 2, PDs 1·5 to 2 were superior to PD 0.
5. The relative weight of the gizzard was reduced by pelleting, whereas pelleting increased the relative weight of abdominal fat. The content of the crop was not affected by PD, whereas that of the proventriculus was lowest in the PD 2 group. Gizzard content was inversely related to PD. Pelleting reduced the length of the jejunum and ileum: which were shortened by about 15% with PDs 1 to 2, as compared to PD 0. The weight/length ratio of the jejunum and ileum tended to increase with increasing PD to a peak at PD 1·5, and to decrease thereafter.
6. Trypsin activity in the pancreas and amylase activity in the intestinal content were reduced by pelleting.
7. Chicks fed pelleted diets were less active: they ‘sat’ more and spent less time eating than their mash‐fed counterparts. 相似文献
2. The dietary treatments had no significant effect upon food intake, egg output, shell thickness, shell deformation or specific gravity of the eggs.
3. The 28‐h cycle reduced mean rate of lay by 4.5%, increased egg weight by 5.8% and increased shell thickness by 9.4%. The proportion of eggs with shell faults revealed on candling was reduced from 4.1 % to 2.8%.
4. It is concluded from this and other sources that decreasing dietary phosphorus or modifying vitamin D supplements may sometimes lead to increases in shell thickness of the order of 1 to 2%, but that these changes are unlikely to result in a measurable reduction in the proportion of cracked eggs late in the laying year.
5. A 28‐h light‐dark cycle results in a longer and more uniform interval between consecutive ovipositions and thus gives reliable increases in shell thickness which are large enough to reduce the proportion of cracked eggs in many practical situations. Whether it is profitable to use an ahemeral cycle will depend upon the relative prices paid for eggs of different sizes. 相似文献
Background
The experiment evaluated the effect of nutrition levels and sex on the growth performance, carcass characteristics and meat quality of F1 Angus × Chinese Xiangxi yellow cattle.Methods
During the background period of 184 d,23 steers and 24 heifers were fed the same ration,then put into a 2 × 2 × 2 factorial arrangement under two levels of - dietary energy (TDN: 70/80% DM), protein (CP: 11.9/14.3% DM) and sex (S: male/female) during the finishing phase of 146 d. The treatments were - (1) high energy/low protein (HELP), (2) high energy/high protein (HEHP), (3) low energy/low protein (LELP) and (4) low energy/high protein (LEHP). Each treatment used 6 steers and 6 heifers, except for HELP- 5 steers and 6 heifers.Results
Growth rate and final carcass weight were unaffected by dietary energy and protein levels or by sex. Compared with the LE diet group, the HE group had significantly lower dry matter intake (DMI, 6.76 vs. 7.48 kg DM/d), greater chest girth increments (46.1 vs. 36.8 cm), higher carcass fat (19.9 vs.16.3%) and intramuscular fat content (29.9 vs. 22.8% DM). The HE group also had improved yields of top and medium top grade commercial meat cuts (39.9 vs.36.5%). The dressing percentage was higher for the HP group than the LP group (53.4 vs. 54.9%). Steers had a greater length increment (9.0 vs. 8.3 cm), but lower carcass fat content (16.8 vs. 19.4%) than heifers. The meat quality traits (shear force value, drip loss, cooking loss and water holding capacity) were not affected by treatments or sex, averaging 3.14 kg, 2.5, 31.5 and 52.9%, respectively. The nutritive profiles (both fatty and amino acid composition) were not influenced by the energy or protein levels or by sex.Conclusions
The dietary energy and protein levels and sex significantly influenced the carcass characteristics and chemical composition of meat but not thegrowth performance, meat quality traits and nutritive profiles. 相似文献2. Two experiments were undertaken for this purpose. In the first experiment, 696 male Ross 708 chickens were reared under standard conditions, and in the second, 750 male JA 657 chickens were reared under Label Rouge conditions. All birds received the same starting and growing diets containing palm and soya oils in each experiment. Birds were distributed into three groups from 21 or 57 d of age for standard and Label Rouge chickens, respectively, and given a control, linseed oil or extruded linseed diet. Diets were also supplemented with vitamin E (100–200 mg/kg). Birds were slaughtered at 56 or 84 d of age for standard and Label Rouge chickens, respectively. A total amount of 60 kg of breast meat from each group was processed into white cured-cooked meat.
3. The dietary treatment had no effect on the growth performance of chickens or meat yield. The use of extruded linseed or linseed oil only decreased the carcass fatness of the standard chickens but had no effect on the carcass fatness of Label Rouge chickens. The nutritional quality of raw and cured-cooked meat was improved (increased concentration of n–3 FA), whereas the technological quality of the meat (pH, juice loss after cold storage, susceptibility to oxidation, colour, processing yield and shear force value) and sensory quality of the processed products were not or slightly affected.
4. Linked to lower breast yield, to lower lipid content in breast meat and to higher slaughter age, Label Rouge chickens seemed to be less efficient for n–3 FA deposition in breast muscles than standard chickens. 相似文献
The objective of this study was to investigate and compare the effects of α-tocopherol acetate (vitamin E (VE)) and microencapsulated VE (MVE) on growth performance, meat quality and antioxidant capacity in broiler chickens.
A total of 360 d-old broiler chicks were procured and randomly allocated into three groups with 6 replicates. Each replicate had 20 chickens. Chickens were fed with basal diets (CON group) or experimental diets supplemented with 20 mg/kg VE (VE group) or 20 mg/kg MVE (MVE group) for 42 d.
The results showed that the MVE group had higher body weight gain (BWG) than the CON and VE groups, and higher gain/feed ratio (G/F ratio) than the CON group during the period of 22–42 d. During the whole experiment, a higher increase in BWG was found in the MVE group than the CON group.
Chickens fed on diets supplemented with the VE or MVE had lower abdominal fat percentage, higher pH and antioxidant enzyme activity than the CON group in the breast meat.
There was an increased tendency in the hepatic glutathione peroxidase (GSH-Px) enzyme activity of the VE and MVE groups than the CON group. The hepatic mitochondrial total antioxidant capacity and GSH-Px enzyme activity in the MVE group were higher than the CON group. Hepatic 2,2-dipheny-?-picrylhydrazyl scavenging activity of the MVE group was higher than the CON group.
These results suggested that the dietary addition of VE or MVE could improve breast meat quality in broilers. MVE supplementation may improve growth performance, hepatic mitochondrial antioxidant capacity and free radical scavenging capacity in chickens. In addition, dietary supplementation of MVE gave better broiler growth performance than VE.
2. Adding 5 μg 1,25‐DHCC/kg to a diet containing 12 g calcium/kg was more effective than early food restriction or meal feeding in preventing leg abnormalities but was found to cause a growth depression.
3. The second experiment, which had a factorial design, with diets containing 7.5, 100 and 12.5 g calcium and 0, 2.0, 3.5 and 5.0 μg 1,25‐DHCC/kg, showed linear and quadratic interactions between these dietary factors. Diets with higher concentrations of both 1,25‐DHCC and calcium resulted in growth depression associated with hypercalcaemia.
4. The incidence of tibial dyschondroplasia (TD) at 3 weeks of age was highest with the basal diet containing 7.5 g calcium/kg and was markedly reduced by addition of 1,25‐DHCC and/or calcium. The incidence was very low or non‐existent when 1,25‐DHCC was fed at 3–5 μg/kg or greater.
5. Feeding 5 μg/kg 1,25‐DHCC had no effect on plasma 1,25‐DHCC concentrations, although at the higher dietary calcium contents plasma concentrations of 25‐hydroxy‐ and 24,25‐dihydroxy‐cholecalciferol were lower in those birds fed 1,25‐DHCC.
6. It is concluded that 1,25‐DHCC is most effective in preventing TD without accompanying growth depression when it is fed in conjunction with diets containing less than 10 g calcium/kg. 相似文献
2. Both cephalosporins and all the nine penicillins tested were active.
3. Of six aminoglycosides, streptomycin and gentamicin had the greatest activity and neomycin had none.
4. Growth rate was significantly improved by clindamycin, lincomycin, vancomycin, spectinomycin, rifampicin, oxytetracycline, chlortetracycline, erythromycin, tylosin, flavomycin, virginiamycin and zinc bacitracin. Chloramphenicol and nalidixic acid were inactive. Polymixin B, novo‐biocin, cycloserine, phosphonomycin, and sodium fusidate had little activity. Fusidic acid promoted growth at 250 mg/kg diet.
5. Trimethoprim was inactive alone and in combination with sulpha‐diazine. Of seven 5‐nitroimidazoles, only dimetridazole and metronidazole showed slight activity. Of the six 5‐nitrofurans, only nitrovin, the standard reference substance used, promoted growth.
6. Caprylohydroxamic acid, a urease inhibitor, had no beneficial effect on growth rate or on the efficiency of food conversion.
7. The growth‐promoting properties of the various substances could not be related with their known antimicrobial and absorption characteristics in mammals. 相似文献
2. GH concentrations were higher in restricted compared with ad libitum‐fed birds at 17 to 21 weeks of age and were similar thereafter. Plasma IGF‐I concentrations were higher in restricted compared with ad libitum‐fed birds throughout the sampling period of the experiment.
3. The age at first egg was delayed by about two weeks in restricted birds. At 54 weeks of age they had laid 114 compared with 67 eggs in birds fed ad libitum throughout and had produced less than half the number of eggs with defective shells.
4. It was suggested that differences in egg production between ad libitum and restricted broiler breeder females could be related to changes in the pattern of GH and/or IGF‐I secretion. 相似文献
2. Force‐feeding significantly increased the weight and area of the crop, the weight of the proventriculus, the length and area of the jejunum and ileum, but decreased the weight of the gizzard and the thickness of its caudodorsal thick muscle. Feeding a barley‐based diet also decreased the thickness of caudodorsal thick muscle of gizzard.
3. Force‐feeding enhanced the absorption rates (μmol/cm2) of glucose and L‐methionine in both jejunum and ileum. Ducks fed on a maize‐based diet showed a slightly higher absorption rate of glucose compared to those fed on a barley‐based diet.
4. Force‐feeding caused a significant increase of endogenous non‐protein nitrogen (μg/cm2/h) in both jejunum and ileum and a slight increase of endogenous protein nitrogen in the jejunum. 相似文献