科研之友
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摘要
whey (sl) spoils rapidly and lactic fermentation is a viable preservation alternative; once fermented, it can be used to feed ruminants. therefore the objectives of the present study were to chemically characterize whey; fermented with lactobacillus casei (slf); and use it for calf feeding. whey was obtained from nine small cheese plants located in the municipalities of cotaxtla and medell赤n de bravo, veracruz, mexico, every 7 d during two months. acidity, ph, protein, fat, lactose and total solids were determined, and the average and standard deviation were calculated. the growth (from 0 to 96 h) of l. casei nrrl b-1922 in whey pasteurized at 63 ～c for 15 min was measured counting the ufc ml-1 in mrs agar. a control (milk intake, 4 l d-1) (t1) was included for comparison purposes: in the addition of whey, 2 l d-1 (t2), or slf, 2 l d-1 (t3); and milk, 1 l d-1, replaced by slf 3 l d-1 (t4), in 24 calves (holstein ℅ zebu) from birth until three months old, in artificial rearing in the tropic (veracruz). average daily weight gain (adg) and concentrate consumption (cc) were monitored. anova was performed with proc mixed (sas) for four treatments and repeated measurements over time. the characteristics of whey (wet basis) were: acidity 2.1㊣0.46 %, ph 5.6㊣1.10, protein 2.2㊣0.52 %, fat 0.5㊣0.22 %, lactose 4.3㊣0.21 % and total solids 7.1 ㊣0.92 %. lactobacilli reached their maximum growth (1 ℅ 107 ufc ml-1) in 24 h. adgs were similar (p%26gt;0.05) in all the calves; but cc in t2 and t3 calves was 38.7 % lower than under t1, and the use of milk in t4 was 25 % lower (p%26lt;0.05). it was concluded that slf with l. casei extended its aerobic stability, and reduced cc without changing the adg in holstein ℅ zebu calves in the tropic.
