Inaugural ASAS–CAAV Asia Pacif ic Rim Conference Abstracts

supplementation of nature plant oil to the diet could increase the content of milkfat. Higher CLA production induced by the SO and LO diets was associatedwith increased SCD gene expression compared with the control, suggesting thatplant oil in the diet may have a coordinating effect with the mammary enzymesinvolved in milk fat synthesis.Key Words: Plant oil, enzymes in mammary tissue, lactating goatT253 Effects of microwave irradiation on in vitro gasproduction kinetics parameters of barley grain. F. Parnian Khajeh Dizaj,A. Taghizadeh*, and H. Paya, Faculty of Animal Science, University of Tabriz,Tabriz, EAzarbijan, East Azerbaijan, Iran.Microwave energy is non-ionizing and causes a rise in the temperature withina penetrated medium as a result of rapid changes of the electromagnetic field(Fakhouri and Ramaswamy, 1993). In many parts of the world, barley grainis an important ingredient in diets for ruminants, serving mainly as an energycomponent, although starch is an excellent substrate for microbial growth inthe rumen. Barley grain samples were adjusted to 30% moisture content by theaddition of an amount of water. Then 3 samples were subjected to microwaveirradiation (900 W) for 3, 5, and 7 min. Rumen fluid was collected from 2fistulated sheep, fed diet containing forage (400 g/kg) plus commercial sheepconcentrate (600 g/kg), 2 h after morning feeding and strained through 4 layersof cheesecloth. Approximately 300 mg of ground and dried barley grain wasweighted, placed in 50-mL-capacity serum bottles, and then incubated in 20mL of Mcdougal buffered rumen fluid (buffer to rumen fluid was 2:1) for 48h in triplicate. Gas production was measured in each vial after 2, 4, 8, 12, 16,24, 36, and 48 of incubation using a water displacement apparatus (Fedorakand Hrudey, 1983). Gas production data was fitted to the model: Y = A(1 – e –ct ).Parameters A and c were estimated by using a nonlinear regression procedureof the statistical analysis systems (SAS, 1999). The A and c fractions arepresented in Table 1. A fraction of barley grain was significantly increasedby microwave irradiation (P < 0.05). There were no differences in thisparameter among times of microwave treatment of barley grain. Microwaveprocessing increased A fraction of barley grain, probably because linkagesbetween the protein matrix and the starch granule were disrupted. It seemsthat microwave treatment increases starch availability and gelatinization.T254 Simultaneous determination of melamine andcyromazine in feeds by gas chromatography–mass spectrometry. B. Shang*,Y. Chen, Z. Wang, W. Yang, and L. Zhang, State Key Laboratory of AnimalNutrition, College of Animal Science and Technology, China AgriculturalUniversity, Beijing, China.Melamine has been of high concern to the public since the occurrence ofmelamine contamination in animal feeds. Cyromazine, an insect growthregulator used as a feed additive to control flies in barns and as a foliar spray tocontrol leafminers on ornamentals and crops, can metabolize via dealkylationin both plants and animals to form melamine. Although several analyticalmethods for melamine and cyromazine have been reported in various matrices,none has been developed for animal feeds yet. This paper describes a gaschromatography–mass spectrometry method for the simultaneous determinationof melamine and cyromazine in feeds. Samples were extracted withtrichloroacetic acid solution, cleaned up by strong cation exchange solid-phaseextraction cartridges and eluted with 0.5% (vol/vol) of ammonium hydroxide/methanol. After elution solution was dried by nitrogen gas, the residue wasredissolved with acetonitrile and derivatized with N,O-bis (trimethylsilyl)trifluoroacetamide and 1% trimethylchlorosilane. Analyses of final solutionswere performed on an Agilent 6890 Plus gas chromatograph equipped witha 5973N mass selective detector operated in electron ionization mode. A DB-5MS capillary column was used for separation, and the following temperatureprogram was employed: 80°C; 20°C/min to 230°C, hold for 2 min; and 30°C/min to 300°C. The characteristic ions for melamine and cyromazine were 99,171, 327, 342, and 171, 181, 295, 310, respectively. The limits of quantificationwere both 0.1 mg/kg while the recoveries of melamine and cyromazine fromspiked complete feeds at levels of 0.1–50 mg/kg ranged from 79.44 to 110.31%with relative standard deviation less than 8%. This validated method wassuccessfully applied to determine commercial feed samples obtained from themarket, indicating that it can be used as a routine tool for surveillance andevaluation of melamine and cyromazine in feeds.Key Words: melamine, cyromazine, gas chromatography–mass spectrometryTable 1. In vitro gas production characteristics of untreated and microwavetreatedbarley grainParameter Untreated 3 min 5 min 7 min SEM (n = 3)A 290.96 b 317.08 a 319.33 a 312.75 a 3.582c 0.1001 a 0.0864 b 0.0877 b 0.0796 c 0.00110a–cMeans within a row with different superscripts differ (P < 0.05).1c = rate of gas production (per hour); A = potential gas production (mL/g ofDM).Key Words: microwave irradiation, barley grain, in vitro gas production72