Effects of extrusion and supplementation of exogenous enzymes to diets containing Chinese storage brown rice on the carbohydrase activity in the digestive tract of piglets

Two experiments were conducted to study the effects of extrusion of Chinese storage brown rice and of exogenous enzymes supplementation to diets containing Chinese storage brown rice on the carbohydrase activity in digestive tract of piglets. In Experiment 1, 96 weaned piglets [initially 6.95 ± 0.05 kg body weight (BW)] were used in a 2 × 2 factorial design, the animals were fed the diets containing extruded Chinese storage brown rice or non‐treated Chinese storage brown rice and supplemented with or without exogenous enzymes. Each treatment had six replicate pens and four piglets in each pen. The results demonstrated that extrusion significantly increased (p < 0.05) the activity of duodenal maltase after 14 days of treatment and glucoamylase after 28 days of treatment, jejunal lactase, maltase, isomaltase, sucrase and α‐amylase after 28 days of treatment, and jejunal α‐amylase after 14 days of treatment; enzyme supplementation positively influenced (p < 0.05) the activity of pancreatic α‐amylase after 14 and 28 days of treatment, pancreatic glucoamylase after 28 days of treatment and ileal trehalase after 14 days of treatment. Similarly, interaction between extrusion and enzyme addition existed after 14 days of treatment on the activity of pancreatic α‐amylase and duodenal maltase and on the activity of duodenal glucoamylase and isomaltase, jejunal α‐amylase, lactase, maltase, isomaltase and jejunal α‐amylase after 28 days of treatment. In Experiment 2, six piglets (initially 21 ± 1.85 kg BW) fitted with ileal ‘T’‐cannulas in a 6 × 6 Latin Square Design were used to study the effects of extrusion and addition of exogenous enzymes on ileal carbohydrase activity and nutrients digestibility. The results showed that exogenous enzymes significantly (p < 0.05) increased ileal α‐amylase, glucoamylase and trehalase activity. The interaction between extrusion and enzyme supplementation had positive effect (p < 0.05) on the ileal lactase, cellobiase and sucrase activity.     

Effect dietary corn starch intake on pancreatic amylase and intestinal maltase and pH in cattle

The pH optimum of pancreatic alpha-amylase from grain-fed steers was determined to be 6.9, while that of intestinal maltase was established at 5.8. Both assays were found to be linear up to 1 hr of incubation. The V max of pancreatic amylase was determined to be pancreatic amylase was determined to be 1.15 mg of maltose monohydrate produced/hr. Activities of pancreatic and intestinal maltase were not reduced (P greater than .05) during the interval from sample collection from the animal until analysis 4 hr later when tissues were kept on ice. Twenty-four yearling Holstein steers fed either alfalfa hay at a maintenance level of metabolizable energy (ME) intake or corn at one, two or three times the maintenance ME intake level were slaughtered after being fed 106 days. The pancreas was removed alone with sections of the intestine. Specific activity of pancreatic amylase for steers fed the high level of corn was 129% of that for steers fed the alfalfa diet (P greater than .05). Intestinal maltase activity was highest in the jejunum and decreased toward the ileum. Increasing dietary starch intake resulted in no response (P greater than .05) in maltase activity at 10, 30, 50, 70, or 90% of the small intestine length. The effect of dietary starch level on dieesta pH was dependent on sampling location within the small intestine. There were no dietary effects (P greater than .05) on digesta pH for the first 10% segment of intestine distal to the pylorus. However, in all subsequent sections, digesta pH was higher steers fed the alfalfa diet than for those fed the two higher levels of grain. A calculation for estimating th amount of pancreatic amylase needed to hydrolyze starch presented to small intestine is discussed.     

胰岛素和酶解配方奶粉对初生仔猪小肠生长发育的影响

为研究胰岛素和酶解配方奶粉是否促进初生仔猪小肠的组织生长和功能成熟,本试验比较了饲喂配方奶粉与饲喂配方奶粉补加胰素或酶解配方奶粉３ｄ后仔猪小肠的重量和长度,组织形态学结构,粘膜ＤＮＡ,ＲＮＡ和蛋白质含量,及小肠内容物中乳糖酶,麦芽糖酶和碱性磷酸酶活性。     

The possible effects of gastro-intestinal nematodes upon intestinal enzymes of calves

Observations were made on the effect of combined infections of gastro-intestinal nematodes on small intestinal disaccharidases and alkaline and acid phosphatases in 4–5-month old Friesian calves. The tests were carried out 3 weeks following exposure of these calves to infected pasture in a wet tropical environment.Sucrase activity, at a very low level, was detected in all parts of the small intestine of infected and uninfected calves. There was no significant difference in maltase, trehalase, cellobiase, sucrase, lactase, acid β-galactosidase, acid and alkaline phosphatase activities between uninfected control calves and all infected calves in which Cooperia species predominated. In heavily infected calves with worm burdens greater than 20 000 Cooperia species significantly elevated (P < 0.05) duodenal maltase and acid phosphatase levels were recorded.     

Effect of human growth hormone-releasing factor and(or) thyrotropin-releasing factor on growth, carcass composition, diet digestibility, nutrient balance, and plasma constituents in dairy calves

Sixty male dairy grain-fed calves, raised from 70 to 223 kg BW in individual crates, were used in a 2 X 2 factorial arrangement to determine the effect of administration of human growth hormone-releasing factor (1-29)NH2 (GRF) and(or) thyrotropin-releasing factor (TRF). Calves received twice-daily s.c. injections of .9% NaCl (control), GRF (5 micrograms/kg BW), TRF (1 micrograms/kg BW) or GRF (5 micrograms/kg BW) plus TRF (1 micrograms/kg GTRF). Average daily gain and days on feed were not affected by treatments, but TRF treatment increased (P less than .05) total intake of dry matter (DM) and feed conversion ratio: 3.00, 3.02, 3.08, and 3.22 kg DM/kg weight gain for control, GRF, TRF, and GTRF, respectively. During two 7-d periods, after 66 and 75 d of treatment, feces and urine were collected from 40 calves (5 per treatment per period). Treatment with GRF increased (P less than .05) digestibility of DM, nitrogen (N), and energy and tended (P less than .20) to increase N retention. At slaughter, withers height was increased (P = .05) by GRF and carcass length was increased (P less than .05) by TRF. Pituitary and liver weights were increased (P less than .05) by TRF. The combination of GRF and TRF slightly increased (P less than .10) protein content and decreased (P less than .05) fat content of the 9-10-11th rib section. After d 1, GRF treatment chronically increased (P less than .05) insulin concentrations and also increased (P less than .10) IGF-I concentrations on d 29 and 57. In summary, chronic treatment with GRF and(or) TRF did not improve growth or efficiency, although GRF increased digestibility of DM, N, and energy and the GRF plus TRF combination resulted in slightly leaner carcasses.     

Effect of dietary protein level on nitrogen metabolism in the growing bovine: II. Diffusion into and utilization of endogenous urea nitrogen in the rumen

Six Angus heifer calves (234 kg) were assigned to either a high (HP; 126.1 g N/d) or low (LP; 66.5 g N/d) protein intake to evaluate ruminal criteria associated with movement of blood urea-N (BUN)-derived NH3-N from the rumen wall into interior ruminal digesta. Calves received 4.8 kg DM/d of diets containing 30% cottonseed hulls and 70% cornsoybean meal in equal portions at 4-h intervals. Following single i.v. injections of 15N-urea, ruminal fluid was collected serially for 4 h postinjection from digesta located adjacent to the rumen wall (wall-proximate digesta; WPD) and from the center of the rumen digesta mass after manual agitation (center mixed digesta; CMD). Mean ruminal NH3-N (RAN) concentrations were higher (P less than .05) for HP than for LP, but were not affected (P greater than .05) by digesta sampling site. Ruminal urease activity was higher (P less than .05) for LP than for HP and tended (P = .14) to be higher for WPD than for CMD. Area under the 15N enrichment curve (AUC) ratios between sampling sites (WPD/CMD x 100) for RAN were greater (P less than .05) for LP than for HP. However, AUC ratios for bacterial N were not affected (P greater than .05) by protein level. Whereas BUN-derived 15NH3 appeared to thoroughly equilibrate with RAN in interior ruminal digesta with HP, there appeared to be a declining enrichment gradient for RAN from the rumen wall to the interior ruminal digesta with LP. Data are interpreted to suggest that bacteria at or near the rumen wall may preferentially utilize some BUN-derived NH3-N entering through the rumen wall in calves fed LP diets.     

Effects of age and diet on the development of the pancreas and the synthesis and secretion of pancreatic enzymes in the young pig

Effects of age and diet composition on amylase, trypsin and chymotrypsin activities in the pancreas and intestinal contents, pancreas weights and body weights were determined from birth to 56 d. A total of 120 pigs, five to seven pigs/litter from 18 litters, were slaughtered at birth, 14, 27, 29, 31, 42 and 56 d. Litters were allotted to dietary treatments (corn-soy, A; corn-soy + 20% dried whey, B; corn-soy + 5% lard, C) and offered these diets as creep feed at 14 d. All pigs were weaned at 28 d, placed in elevated nursery pens and fed their respective diets. Total activities of amylase, trypsin and chymotrypsin in the pancreas and small intestine increased (P less than .05) with age. Both trypsin and amylase activities, measured per kilogram body weight or gram pancreas weight, were low at 29 d in the intestine and increased to 56 d. Pigs on diet B had the highest level of trypsin and chymotrypsin in the intestinal contents (P less than .05). Trypsin activity in the pancreas (units/kg body weight) was lowest (P less than .05) for pigs on diet B and highest (P less than .05) for those on diet C (units/g pancreas and units/kg body weight). Amylase activity (units/kg body weight) was lower (P less than .05) in the pancreas for pigs on diet B than for those on diets A and C. Pigs on diet A had lower (P less than .01) intestinal amylase activities than those on diets B and C. Enzyme activities in the intestinal contents and pancreas were low following weaning. In the pancreas, activities decreased at 31 d.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of feeding different protein-free diets on the recovery and amino acid composition of endogenous protein collected from the distal ileum and feces in pigs

Nine barrows with an average initial weight of 60 kg were fitted with simple T-cannulas at the distal ileum. The animals were fed four different protein-free diets according to an incomplete latin square design. Diet 1 (control diet) consisted of 79.7% cornstarch, 10% sucrose, 3% Alphafloc (a source of cellulose), 3% canola oil and a vitamin-mineral premix. Diets 2, 3 and 4 contained, respectively, 4% pectin, an additional 7% cellulose and an additional 10% canola oil, each included at the expense of cornstarch. Feces were collected during 3 d following a 7-d adaptation period. Thereafter, digesta were collected during two 24-h periods with a 24-interval between periods. The pigs were fed 800 g of feed twice at 0800 and 2000. Added pectin increased (P less than .05) the recovery of endogenous protein in ileal digesta from 19.8 diet (diet 1) to 24.0 g per kg dry matter intake. This increment was largely due to increases (P less than .05) in glycine and proline from 1.9 to 2.4 and from 6.2 to 8.4 g per kg dry matter intake, respectively. In feces, only added cellulose increased (P less than .05) excretion of endogenous protein (8.4 vs 11.1 g/kg DM intake) and of most amino acids. Including additional fat did not affect the quantity of endogenous protein and amino acids recovered in ileal digesta or feces. Small but significant differences (P less than .05) were observed in the amino acid composition of endogenous protein recovered in ileal digesta when the different protein-free diets were fed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aflatoxin B1 toxicosis in dairy calves pretreated with selenium-vitamin E

Effects of a single IM injection of selenium-vitamin E (Se-E; 5 mg of Se + 68 IU of alpha-tocopherol/60 kg of body weight) as a pretreatment 14 days before an oral dose of aflatoxin B1 (1.0 mg/kg) were studied in 24 dairy calves. Treatment groups were designated as follows: group 1 = no Se-E or aflatoxin B1 (control); group 2 = Se-E supplementation only; group 3 = aflatoxin B1 dose only; and group 4 = Se-E supplementation before aflatoxin B1 dose. Clinical signs of toxicosis in aflatoxin B1-treated calves included anorexia, ataxia, rough haircoats, increased respiration rates, dyspnea, dehydration, and nasal discharge. Packed-cell volume, RBC, WBC, and hemoglobin were increased in aflatoxin-treated calves. Significant increases in serum aspartate aminotransferase (P less than 0.05) and gamma-glutamyl-transferase (P less than 0.001) activities and prothrombin times (P less than 0.001) were observed in aflatoxin-treated calves, indicating that there was hepatic involvement. Although aflatoxin exposure caused a significant decrease in body weight (P less than 0.01) and feed intake (P less than 0.001) in treatment groups 3 and 4, Se was demonstrated to interact significantly (P less than 0.001) with aflatoxin B1 for feed intake, causing an improved feed intake in treatment group 4 calves.     

抗菌肽对发酵床饲养仔猪生长性能、消化酶及垫料理化性质的影响

试验旨在研究发酵床饲养模式下饲粮中添加抗菌肽对仔猪生长性能、胰腺和小肠内容物消化酶及小肠黏膜二糖酶和垫料蛋白酶、脲酶、铵态氮的影响。选用108头35日龄、体重13kg左右的健康苏钟猪随机分为3组,每组3重复,每重复12头,分别饲喂基础饲粮（对照组）、基础饲粮＋40mg/kg杆菌肽锌＋20mg/kg硫酸黏杆菌素（抗生素组）和基础饲粮＋300mg/kg抗菌肽（抗菌肽组）的试验日粮,试验期49d10结果表明：（1）各组间仔猪生长性能差异不显著（P〉0.05）。（2）与对照组相比,饲粮中添加抗菌肽能够显著提高仔猪胰腺、十二指肠和空肠内容物淀粉酶及空肠内容物胰蛋白酶活性（P〈0.05）;并显著提高仔猪十二指肠黏膜麦芽糖酶和空肠黏膜蔗糖酶、乳糖酶及回肠黏膜蔗糖酶活性（P〈0.05）;抗菌肽组十二指肠黏膜麦芽糖酶活性比抗生素组提高（P〈0.05）。（3）各组间发酵床垫料蛋白酶和脲酶活性及铵态氮含量差异不显著（P〉0.05）。综上所述,本试验条件下,饲粮添加300mg/kg的抗菌肽能够在一定程度上提高仔猪生长性能;提高胰腺、小肠内容物及小肠黏膜消化酶活性;同时不影响垫料蛋白酶、脲酶活性和垫料铵态氮含量。     

Output/input differences among nonpregnant, lactating Bos indicus-Bos taurus and Bos taurus-Bos taurus F1 cross cows

Nonpregnant F1 crossbred cows, progeny of either Hereford (H) or Angus (A) dams and sired by Brahman (Bm), Sahiwal (Sw), Pinzgauer (Pz), H, or A sires, were fed to maintain initial weight while rearing Charolais (C)-sired progeny for a period of 126 d in drylot commencing at about 48 d postpartum. Cow-calf pairs were assigned to equalize cow age, calf sex, and breed of cow's dam among three replicate pens of approximately 12 pairs each. Cows and calves were weighed every 2 wk and feed intake was adjusted to minimize change in cow weight. Metabolizable energy (ME) consumption for zero cow weight change was estimated by regression. Milk production was estimated by weight-suckle-weigh at 58, 85, 125, and 170 d of lactation. Calf gain (GAIN, kg) relative to cow weight (CWT1, kg) was higher (P less than .01) for calves from Bm-X (139.5/585) and Sw-X (132.2/534) than for calves from Pz-X (127.2/552) and HA-X (116.9/547) cows. Estimated mean daily production of milk was 7.40, 7.15, 7.28, and 6.37 kg for the Bm-X, Sw-X, Pz-X, and HA-X, respectively. Total cow ME intake (TMEcow) for breed groups ranked (P less than .05) with cow size and milk production, and calf creep-feed intake (FMEcalf) was inversely related to estimated milk intake. Proportion of total feed ME (TMEcow+calf) consumed by calves was higher (P less than .05) for HA-X cows (18%) than for the others (14%). Total efficiency of calf gain in weight (GAIN/TMEcow+calf) was 11% greater (P less than .05) for crossbred cows of Bos indicus X Bos taurus (Bm-X, Sw-X) than for Bos taurus X Bos taurus (Pz-X, HA-X) cows (35 vs 32 g/Mcal) in the 126-d lactation period.     

小麦可溶性非淀粉多糖对肉仔鸡小肠粘膜二糖酶活性的影响

在体内、外研究了小麦可溶性非淀粉多糖(SNSP)对肉仔鸡小肠粘膜二糖酶活性的影响。取1日龄黄羽肉鸡105羽,随机分为3组,饲喂由玉米—豆粕、小麦—豆粕和玉米—豆粕加小麦SNSP提取物组成的3种日粮 ,分别于1、4、7、10、14、18和21日龄宰杀 ,取小肠粘膜 ,测定5种粘膜二糖酶的活性。体内试验结果表明 ,与玉米—豆粕日粮相比 ,小麦—豆粕日粮对肉仔鸡小肠粘膜乳糖酶、麦芽糖酶和纤维二糖酶活性抑制作用显著 (P<0.05)。玉米—豆粕加小麦SNSP提取物日粮对肉仔鸡小肠粘膜麦芽糖酶活性抑制作用显著 (P<0.05)。体外试验结果表明 ,小麦木聚糖显著降低乳糖酶、蔗糖酶、海藻糖酶和纤维二糖酶的活性 (P<0.05) ,极显著降低麦芽糖酶的活性 (P<0.01)。桦木木聚糖和小麦SNSP提取物分别显著降低蔗糖酶、海藻糖酶和纤维二糖酶的活性 (P<0.05) ,极显著降低麦芽糖酶的活性 (P<0.01)。研究结果表明 ,小麦SNSP无论在体内或在体外 ,均可抑制肉仔鸡小肠粘膜二糖酶活性。抑制小肠粘膜二糖酶活性是小麦SNSP抗营养作用的重要机制之一。     

Relationships of weight gain and behavior to digestive organ weight and enzyme activities in piglets

Organ weights and digestive enzyme contents of the pancreas, stomach and duodenum were measured in 75 nursing piglets at 21 d of age. Piglets were given creep feed from 10 d of age. Creep feed intake was less than 1.5 g.d-1.piglet-1 up to d 18; on d 19 and 20 it averaged 15 g.d-1.piglet-1. On d 10, piglets went to the feeder more frequently than on the following days. Feeding bouts were longer on d 16, 17 and 18 just prior to the increase in creep feed consumption. Means and SE for the parameters studied at 21 d of age were 7.01 +/- .18 mg for pancreas weight; 61,499 +/- 4,091 units of amylase (UA) and 1,510 +/- 110 UA/mg DNA; 2,962 +/- 189 units of chymotrypsin (UC) and 68.94 +/- 3.92 UC/mg DNA; 8.76 +/- .35 g for fundic mucosa weight; 558,875 +/- 49,287 units of pepsin (UP) and 12,338 +/- 1,175 UP/mg DNA; 1.75 +/- .06 g for duodenum weight; 1.39 +/- .07 units of maltase (UM) and .14 +/- .006 UM/mg DNA. Day-0 weight was not correlated with 21-d gain. Feeding behaviors were correlated positively with 21-d gains. Feeding behaviors and behaviors were correlated positively to pancreas total and specific enzyme contents as well as to stomach and duodenum weights, RNA/DNA ratios of the pancreas and the stomach and protein/DNA of the pancreas but were correlated negatively with specific and total pepsin and maltase activities. Variation was large in enzyme activities (cv = 35 to 82%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of disaccharidase activity in the small intestine of broiler chickens

1. The changes in disaccharidase activity in the small intestine of broiler chickens were investigated in isolated enterocytes on d 18 of embryonic development and d 1, 7, 21, 35 and 56 after hatching. 2. The specific activities of maltase, lactase and trehalase were greatest on d 18 of embryonic development. After hatching, maltase specific activity gradually decreased until d 18. 3. After d 7 postnatally only traces of lactase and trehalase activity were found in the enterocytes. 4. Significant sucrase activity was found on d 18 of embryonic development and the activity of this enzyme increased 2-fold after hatch and remained generally constant up to d 35, after which the enzyme specific activity declined.     

Traits affecting postweaning weight gain and feed intake of primiparous sows

Seventy-six primiparous Duroc and Landrace sows from two genetic lines with or without selection for improved sow productivity were used to identify sow traits that affect postweaning gain (positive or negative) and feed intake. Sows lost weight (P less than .01) and consumed less feed (P less than .01) during wk 1 postweaning (37 d) compared with wk 2, 3, and 4. Sows gained more weight during wk 2 and 3 (P less than .01) than during wk 4. Weekly feed consumption was similar during wk 2 and 4 and highest during wk 3 (P less than .05). Sow weight gain postweaning was predicted by sow weaning weight (P less than .01) and adjusted 21-d litter weight (P less than .05) during wk 1, wk 1 to 2, and wk 1 to 4 feeding periods. Feed consumption was best predicted by adjusted litter weaning weight (P less than .01), sow weaning weight (P less than .01), average backfat at farrowing (P less than .01), average backfat change (P less than .05), and adjusted 21-d litter weight (P less than .05). Feed intake was positively correlated (P less than .01; r = .77) and sow weight at breeding, farrowing, and weaning was negatively correlated (P less than .05; r = -.23, -.21, and -.26, respectively) with sow weight gain. Average backfat at weaning was negatively correlated (P less than .05) with gain and feed intake during each period. Adjusted 21-d litter weight and adjusted litter weaning weight were positively correlated with postweaning feed intake (P less than .05; r = .22 and .23, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Summer fescue toxicity in dairy steers fed tall fescue seed

Seeds of the tall fescue ( Festuca arundinacea Schreb .) cultivars Kentucky 31 and an experimental ryegrass X tall fescue hybrid derivative strain (G1-307), and orchard grass (OG) seed were fed in a carrier diet to calves in controlled environmental rooms (31 to 32 C). Both tall fescue varieties produced symptoms of summer toxicosis in dairy steers. Total feed intake (P less than .01) and water intake (P less than .01) of calves were reduced by the tall fescue seed diets when compared with orchard grass. Steers fed G1-307 and Kentucky 31 tall fescue lost (NS) 17.5 and 7.8 kg of body weight, respectively, while those consuming orchard grass gained (P less than .01) 6.2 kg during the experiment. Rectal temperatures were lower (P less than .05) in the calves fed OG (39.4 C) when compared with those fed G1-307 (40.6 C) and Kentucky 31 (40.8 C) tall fescue seed, respectively. In a second trial Kentucky 31 seed was fed in a carrier diet to Holstein steers at graded levels of 0, 350, 700 and 1,050 g seed/d. Consumption of 700 and 1,050 g seed/d adversely affected performance of steers. Total feed intake was lower and water intake was reduced (P less than .05), with rectal temperatures being elevated (P less than .01) in these two groups when compared with 0- or 350-g treatments. No significant differences were detected in body weight changes in this trial. Respiration rates were not significantly affected in either trial. Results of these trials with the young bovine indicate that a toxic substance(s) is present in tall fescue seed.     

Effects of milk intake on forage intake and performance of suckling range calves

A study to examine the relationships between milk intake, forage intake, and performance of Hereford-Angus suckling range calves was conducted during July, August, and September of 1984 and 1985. Twenty calves were used each year. The study was conducted at the Red Bluff Research Ranch located 56 km west of Bozeman, Montana. Average daily gain, milk intake (MI), forage digestibility, and fecal output (FO) were measured at 28-d intervals, beginning when the average calf age was 66 +/- 4 d. Milk intake was estimated using weigh-suckle-weigh techniques. Total fecal collections were used to measure FO. Forage digestibility and rates of passage were determined using nylon bag in situ techniques and external markers in ruminally cannulated calves of the same age. Fecal output by calves increased as body weight and age increased. Milk intake was higher (P less than .05) in 1985 than in 1984, but FO was higher (P less than .01) in 1984 than in 1985. Fecal output by calves was negatively correlated to MI in July (r = -.62; P less than .05) and August (r = -.56; P less than .05). No significant correlations were detected between MI and ADG (P greater than .10). Forage intake estimates were derived from FO, rate of passage, and in situ digestibility values. During July, calves consumed .3 kg more forage for each kilogram of reduction in fluid MI (P less than .05). In both August and September, calves consumed .6 kg more forage for each kilogram of reduction in fluid MI (P less than .10). Calves maintained similar digestible energy (DE) intake both years, although the source of DE varied.     

Effect of glucocorticoids and limiting nursing on the carbohydrate digestive capacity and growth rate of piglets

The influence of glucocorticoid administration and limited nursing on piglet carbohydrase enzyme development and subsequent growth was examined in three experiments using 371 piglets. Treatments in the first two experiments were formed by the factorial arrangement of hydrocortisone (-HYD or +HYD) and limited nursing (-LN or +LN) imposed form d 14 to weaning (d 28). Hydrocortisone was replaced by adrenocorticotropic hormone (ACTH) in the third experiment. Growth rates were severely depressed by HYD (P less than .01), LN (P less than .001) and to a lesser extent (P less than .06) by ACTH during the last 2 wk of lactation. During the first 14 d postweaning, piglets continued to grow more slowly following HYD treatment (P less than .01), whereas LN piglets grew more rapidly than those allowed to suckle normally. Although piglets were smaller at weaning after HYD injection (P less than .01), relative weights of liver, pancreas and small intestine were increased (P less than .05). Only adrenal weights were increased by ACTH (P less than .09). Pancreatic and intestinal amylase activities were increased two- to three-fold by HYD injection (P less than .05) but were unaffected by ACTH or LN (P greater than .10). Sucrase and maltase activity increased linearly with age (P less than .001). This rate of increase was numerically enhanced by glucocorticoid treatment and LN. The normal decrease in lactase activity was accelerated by LN and HYD injection, with the greatest depression caused by the combination of LN and either HYD or ACTH administration (P less than .05). Glucocorticoid administration to nursing piglets can evoke premature elevation of the carbohydrase enzymes necessary for initiating the hydrolysis of starch.     

Effect of a hay and a grain diet on the rate of hydrolysis of ochratoxin A in the rumen of sheep

The hydrolysis of ochratoxin A (OA) and the corresponding formation of its hydrolysis product, alpha ochratoxin (O alpha), by ruminal digesta and in the rumen of hay-fed and grain-fed sheep were compared. Ruminal contents from sheep fed diets with hay or with grain hydrolyzed OA in vitro; the majority of the activity was associated with the particulate fraction of the ruminal contents. The rate of hydrolysis of OA by ruminal fluid that was adjusted to different pH values was not influenced (P greater than .6) by the pH of the samples (pH was from 5.5 to 7.0). Ruminal fluid obtained from hay-fed animals (pH 7.0) was able to hydrolyze OA in vitro and to produce the hydrolyzed product, O alpha, at a much greater rate (fivefold) than ruminal fluid obtained from grain-fed animals (pH 5.5) (P less than .01). Ochratoxin A was administered intraruminally at a concentration of .5 mg/kg of BW to hay-fed and grain-fed sheep. The half-lives for disappearance of OA from the rumen of sheep fed grain (normal feed intake, rumen pH 5.7), fed grain at a low level (30% of normal feed intake, pH 6.5), and fed hay (pH 7.1) were 3.6, 1.3, and .6 h, respectively. The results suggest that OA is hydrolyzed much faster in the rumen of sheep fed hay than in sheep fed grain, presumably because of the different ruminal microbial population, which in turn influenced the rate of hydrolysis of OA.     

Effect of decreased feed intake on serum and pancreatic alpha-amylase of broiler chickens

Removal of feed from 20-day-old broiler chicks for 24 hours caused serum and pancreatic alpha-amylase activities to increase almost twofold. A 24-hour feeding period following feed removal caused a reduction in serum alpha-amylase to basal levels and a sixfold reduction in pancreatic alpha-amylase activity. Serum alpha-amylase levels remained elevated after long-term feed restriction in adult broilers compared with levels in full-fed controls. Reduction in feed intake in chicks caused by coccidial infections also resulted in increased serum alpha-amylase. In all cases, the degree of change in serum alpha-amylase corresponded inversely to feed intake. It is proposed that the pancreas synthesizes a specific quantity of alpha-amylase, which does not change even under conditions of extended underconsumption of feed. The rate of alpha-amylase secretion is determined, at least indirectly, by the rate of carbohydrate metabolism, and the remainder of the enzyme is stored in the pancreatic cells. A small percentage of the stored enzyme diffuses into the blood and thus directly reflects increased secretion or accumulation of alpha-amylase in the pancreas in response to conditions of carbohydrate utilization.