METHODS: One-hundred-and-twenty male broiler chicks from each strain (one-day-old) were randomly assigned in groups of 10 to 24 battery cages. Ambient temperature on day (d) 1 was set at 32°C and gradually reduced to 23°C on d 21. From d 22 to 35, equal numbers of birds from each strain were exposed to a temperature of either 23°C throughout (normal) or 34°C for 6 h (heat stress).
RESULTS: From d 1 to 21, strain had no effect (p>0.05) on feed intake (FI), body weight gain (BWG), or the feed conversion ratio (FCR). Except for creatine kinase, no strain×temperature interactions were observed for all the parameters measured. Regardless of strain, heat exposure significantly (p<0.05) reduced FI and BWG (d 22 to 35 and 1 to 35), immunoglobulin Y (IgY) and IgM, while increased FCR (d 22 to 35 and 1 to 35) and serum levels of glucose and acute phase proteins (APPs). Regardless of temperature, the Ross 308 birds had significantly (p<0.05) lower IgA and higher finisher and overall BWG compared to Cobb 500.
CONCLUSION: The present study suggests that the detrimental effects of heat stress are consistent across commercial broiler strains because there were no significant strain×temperature interactions for growth performance, serum APPs and immunoglobulin responses, meat quality, and ceacal microflora population.
METHODS: A total of 120 male broiler chickens (Cobb 500) were assigned to a 2×3×2 factorial arrangement in a completely randomized design using two restraint methods (shackle and cone), three durations of restraint (10, 30, and 60 s), and two categories of live body weight (1.8±0.1 kg as lightweight and 2.8±0.1 kg as heavyweight).
RESULTS: Irrespective of the duration of restraint and body weight, the coned chickens were found to have lower plasma corticosterone (p<0.01), lactate (p<0.001), lower meat drip loss (p<0.01), cooking loss (p<0.05), and higher blood loss (p<0.05) compared with their shackled counterparts. The duration of restraint had significant effects on the meat initial pH (p<0.05), ultimate pH (p<0.05), and yellowness (p<0.01). The lightweight broilers exhibited higher (p< 0.001) blood loss and lower (p<0.05) cooking loss compared to the heavyweight broilers, regardless of the restraint method used and the duration of restraint. However, the interaction between the restraint method, duration of restraint, and body weight contributed to differences in pre-slaughter stress and meat quality. Therefore, the interaction between the restraint method and the duration of restraint affected the meat shear force, lightness (L*) and redness (a*).
CONCLUSION: The duration of restraint and body weight undoubtedly affect stress responses and meat quality of broiler chickens. Regardless of the duration of restraint and body weight, the cone restraint resulted in notably lower stress, lower meat water loss, and higher blood loss compared to shackling. Overall, the findings of this study showed that restraint method, duration of restraint, and body weight may affect the stress response and meat quality parameters in broilers and should be considered independently or interactively in future studies.
METHODS: Twenty-four Dorper lambs (18.68±0.6 kg, 4 to 5 months old) were randomly assigned to a concentrate mixture containing either, no supplement (control, T1), 1% Rosmarinus officinalis leaves (T2), 1% Nigella sativa seeds (T3), or 1% Rosmarinus officinalis leaves+1% Nigella sativa seeds (T4) on a dry matter basis. The lambs were fed the treatments with urea-treated rice straw for 90 days, slaughtered and the muscles were subjected to a 7 d postmortem chill storage.
RESULTS: The T2 lambs had greater (p<0.05) slaughter and cold carcass weights than the control lambs. Dietary supplements did not affect (p>0.05) chill loss, dressing percentage, carcass composition, intramuscular fat and muscle pH in Dorper lambs. Meat from supplemented lambs had lower (p<0.05) cooking and drip losses, shear force, lightness, and lipid oxidation and greater (p<0.05) redness compared with the control meat. The impact of dietary supplements on muscle FA varied with muscle type. Diet had no effect (p>0.05) on the expression of stearoyl-CoA desaturase and lipoprotein lipase genes in LD and ST muscles in Dorper lambs. The T2 and T3 diets up regulated the expression of AMP-activated protein kinase alpha 2 gene in LD and ST muscles and up regulated the expression of sterol regulatory element-binding protein 1 in ST muscle in Dorper lambs.
CONCLUSION: Dietary supplementation of Nigella sativa seeds and Rosmarinus officinalis leaves had beneficial effects on meat quality in Dorper lambs.
METHODS: Corn was harvested at four growth stages; silking, milk, dough, and dent stages from four varieties; Sweet Corn hybrid 926, Suwan, breeding test line (BTL) 1 and BTL 2. Using a split plot design, the treatments were then analysed based on the plant growth performance, yield, nutritive and feeding values followed by a financial feasibility study for potential commercialization.
RESULTS: Significant differences and interactions were detected across the parameters suggesting varying responses among the varieties towards the harvest stages. Sweet Corn was best harvested early in the dough stage due to high dry matter (DM) yield, digestible nutrient, and energy content with low fibre portion. Suwan was recommended to be harvested at the dent stage when it gave the highest DM yield with optimum digestible nutrient and energy content with low acid detergent fibre. BTL 1 and BTL 2 varieties can either be harvested at dough or dent stages as the crude protein, crude fibre, DM yield, DM content, digestible nutrient and energy were not significantly different at either stage. Further financial analysis showed that only Sweet Corn production was not financially feasible while Suwan had the best financial appraisal values among the grain varieties.
CONCLUSION: In conclusion, only the grain varieties tested had the potential for silage making according to their optimum harvest stage but Suwan is highly recommended for commercialization as it was the most profitable.
METHODS: Twelve 3 to 4 months old male goats and sheep were randomly allocated into two dietary treatment groups in a 2 (species)×2 (oil levels) factorial experiment. The treatments were: i) goats fed basal diet, ii) goats fed oil-supplemented diet, iii) sheep fed basal diet, and iv) sheep fed oil-supplemented diet. Each treatment group consisted of six animals. Animals in the basal diet group were fed with 30% alfalfa hay and 70% concentrates at a rate equivalent to 4% of their body weight. For the oil treatment group, linseed oil was added at 4% level (w:w) to the concentrate portion of the basal diet. Growth performance of the animals was determined fortnightly. Digestibility study was conducted during the final week of the feeding trial before the animals were slaughtered to obtain rumen fluid for rumen fermentation characteristics study.
RESULTS: Sheep had higher (p<0.01) average daily weight gain (ADG) and better feed conversion ratio (FCR) than goats. Oil supplementation did not affect rumen fermentation in both species and improved ADG by about 29% and FCR by about 18% in both goats and sheep. The above enhancement is consistent with the higher dry matter and energy digestibility (p<0.05), as well as organic matter and neutral detergent fiber digestibility (p<0.01) in animals fed oil- supplemented diet. Sheep had higher total volatile fatty acid production and acetic acid proportion compared to goat.
CONCLUSION: The findings of this study suggested that sheep performed better than goats when fed a fattening diet and oil supplementation at the inclusion rate of 4% provides a viable option to significantly enhance growth performance and FCR in fattening sheep and goats.
METHODS: Two physical treatments, namely extrusion (using temperature profiles of 90°C/100°C/100°C, 90°C/100°C/110°C, and 90°C/100°C/120°C) and sieving (to 8 particles sizes ranging from >8.00 to 0.15 mm) were carried out to determine their effects on chemical properties, primarily crude protein (CP) and fiber contents of PKC. Based on the results from the above study, PKC that extruded with temperature profile 90/100/110°C and of sieved size between 1.5 to 0.15 mm (which made up of near 60% of total samples) were used to determine treatments effect on AME and CP and amino acid digestibility. The second stage experiment was conducted using 64 male Cobb 500 chickens randomly assigned to 16 cages (4 cages [or replicates] per treatment) to the following four dietary groups: i) basal (control) diet, ii) basal diet containing 20% untreated PKC, iii) basal diet containing 20% extruded PKC (EPKC), and iv) basal diet containing 20% sieved PKC (SPKC).
RESULTS: Extrusion and sieving had no effect on CP and ash contents of PKC, however, both treatments reduced (p<0.05) crude fiber by 21% and 19%, respectively. Overall, extrusion and sieving reduced content of most of the amino acids except for aspartate, glutamate, alanine and lysine which increased, while serine, cysteine and tryptophan remained unchanged. Extrusion resulted in 6% increase (p<0.05) in AME and enhanced CP digestibility (p<0.05) by 32%, as compared to the untreated PKC while sieving had no effect on AME but improved CP digestibility by 39% which was not significantly different from that by extrusion.
CONCLUSION: Extrusion is more effective than sieving and serves as a practical method to enhance AME and digestibility of CP and several amino acids in broiler chickens.
METHODS: The innovative sous vide treatments were cooked at 45°C and 65°C for 6 h (SV45-65), common sous vide treatment at 45°C and 65°C for 3 h (SV45 and SV65) and traditional cooking at 75°C for 30 min (CON75). Water loss and cooking loss, as well as the physical properties (color and shear force) and chemical properties (protein and collagen solubility) of the treated meat, were investigated.
RESULTS: The results obtained indicated that the innovative sous vide with double thermal treatment (SV45-65) and cooked with air presence (CON75) resulted to lower a* and higher b* values, respectively. The water loss and cooking loss increased when temperature increased from 45°C to 65°C, and lower water loss was recorded in SV45 and CON75. These samples presented higher water content and revealed strong correlation to protein solubility. Warner-Bratzler shear force (SF) analysis showed the marked interaction between cooking temperature and time. Sample cooked at a high temperature (CON75) and a long period (SV45-65) showed a significantly lower value of SF than sample SV65 (p<0.05). Interestingly, there was no difference in SF values between SV45-65 and CON75.
CONCLUSION: The innovative sous vide treatment with double thermal effect appears an attractive cooking method as compared to common sous vide and traditional cooking method, as it has a potential for improving tenderness values of cooked beef semitendinosus muscle.