Age-related changes in jejunal glucose absorption in mice

Effects of replacing soybean meal with linseed meal in broiler diet on selected broilers’ blood parameters, meat chemical composition, fatty acid profiles, and sensory characteristics

The study was conducted with the objective of determining the effects of the dietary replacement of soybean meal with graded levels of linseed meal on selected blood parameters, meat composition, fatty acid profiles, and meat quality of broiler chickens. Cobb500 broilers were fed diets containing linseed meal at 0% (T1), 6.5% (T2), 13% (T3), 19.5 (T4), and 26% (T5), replacing 0% to 100% soybean meal in compound rations for 45 days. The experiment was conducted using a completely randomized design with five treatments, each replicated three times with 12 birds. Blood hematological indices were not affected (P>0.05) by treatment diets while among the blood biochemistry triglyceride and cholesterol concentrations in T1 were higher (P<0.05) than in T3, T4, and T5. Glucose was higher in T3, T4, and T5 than in T1 and T2 (P<0.01). The breast and thigh proximate composition for crude protein (CP), ether extract (EE), ash, carbohydrate, and gross energy were similar (P>0.05) among treatments. The sensory scores for breast and thigh meat samples were not different (P>0.05) among treatments. The palmitic acid content of breast and thigh meat was higher (P<0.05) in T1 and T2 than in the other treatments. Eliadic and stearic acid concentrations in thigh meat were greater (P<0.05) in T1, T2, and T3 than in T4 and T5. The oleic and linoleic acid contents of thigh meat were higher (P<0.05) in T2 and T3 than in the rest of the treatments. Breast linolenic acid was high (P<0.05) in T5 but similar in thigh meat. Total saturated fatty acid (SFA) showed a decreasing trend with an increasing level of linseed meal (LSM) in the ration. The ratio of monounsaturated fatty acid (MUFA) to SFA for breast and thigh was higher in T4 and T5 than in T1 and T2. Breast meat ratio of omega-6 (n-6) to omega-3 (n-3) showed a decreasing trend as the level of LSM replacement for soybean meal (SBM) in the ration increased. Generally, linseed meal replacement levels up to 26% in the broilers’ diet improves the essential fatty acid content of chicken meat without affecting the proximate composition and the chickens’ normal blood indices and does not alter meat sensory attributes.

Ionophores have limited effects on jejunal glucose absorption and energy metabolism in mice

Two experiments, Trial 1 (in vitro) and Trial 2 (in vivo), were conducted to examine the effects of ionophores, monensin, laidlomycin, and laidlomycin propionate on whole-animal O2 consumption, organ weights, jejunal glucose absorption, and O2 utilization, as well as growth, feed and water consumption, and feed efficiency. In Trial 1, 30 male Swiss-Webster mice, 8 wk old, were used to measure the in vitro effects of each of the ionophores at concentrations of 1.62 or 16.2 mM. Six combinations of three ionophores at two concentrations resulted in a total of eight treatments. All eight treatments were exposed to jejunal rings from a single mouse for a total of 30 observations per treatment. Jejunal rings were exposed to each ionophore treatment for 15 min. Laidlomycin propionate (16.2 mM) decreased (P < 0.02) glucose absorption, as estimated by H3-3-O-methyl glucose uptake compared with all other treatments, whereas laidlomycin propionate (1.62 mM) increased (P = 0.032) jejunal DM content compared with 16.2 mM laidlomycin propionate. In Trial 2, 40 5-wk-old mice were allotted into four treatments--control and 16.2 mM each of monensin, laidlomycin, and laidlomycin propionate--for a total of 10 observations per treatment. Ionophores were administered via the drinking water for 14 d. No ionophore treatment had any effect on whole-mouse O2 consumption. Monensin increased (P = 0.004) stomach size and decreased (P = 0.049) the efficiency of BW gain compared with controls. Laidlomycin propionate decreased (P = 0.032) the percentage of whole jejunum oxygen consumption due to oubain-sensitive respiration compared with control. The efficiency of intestinal glucose absorption was not changed due to treatment in either trial. Under the conditions of these studies, monensin, laidlomycin, and laidlomycin propionate had minimal and inconsistent effects on jejunal function and energy utilization in mice. This investigation suggests that changes in the energetic requirements of animals treated with ionophores are not an issue in animal production.

Jejunal glucose uptake and oxygen consumption in turkey poults selected for rapid growth

Two lines of turkey poults, one selected for rapid growth at 16 wk of age (F line) and the other a randombred control line (RBC2) were used to investigate the effect of selection for rapid growth on jejunal O2 consumption and glucose transport as well as whole-body O2 consumption. All trials used unsexed poults and were designed as a randomized complete block with day and line as independent variables. In Trial 1, 120 turkey poults, fed a standard starter ration (25.5% CP), were used to examine the effect of selection on feed intake, body weight gain, and efficiency from hatching (Day 0) to 13 d of age. At Day 14, 36 of 60 birds from each line were killed to measure intestinal length and weight and jejunal O2 consumption after 18 h of feed deprivation. Compared with the RBC2 line, the F line had relatively shorter but heavier small intestinal segments when adjusted by 18 h feed-deprived body weight (FBW; P < 0.001). The F line consumed more O2 over the entire jejunum adjusted to FBW than RBC2 line (43.8 vs 34.6 nmol O2/min.g FBW; P < 0.001). Jejunal ouabain- and cycloheximide-sensitive O2 consumption were greater (P < 0.05) in the F line. In Trial 2, 16 14-d-old poults from each line were used to measure in vitro jejunal glucose transport rate. There was no difference in glucose transport of the jejunum (nanomoles per minute per gram of FBW) between the lines. In Trial 3, 20 poults from each line were used to measure whole-body O2 consumption at 7 to 10 d of age. The F and RBC2 lines had similar whole-body O2 consumption rate per gram of FBW. These data suggest that selection of turkeys for rapid growth at 16 wk of age did not increase efficiency of jejunal glucose uptake in 14-d-old turkey poults.

Uptake capacity in vitro for glucose and methionine and in situ for oleic acid in the proximal small intestine of posthatch chicks

The uptake capacity of the duodenum and jejunum was determined in vitro for glucose and methionine using 14C-inulin as an unabsorbed reference substance in posthatch chicks. Fatty acid uptake in situ was also determined in the duodenum. Methionine uptake capacity increased in both duodenum and jejunum between hatch and 7 d and was constant between 7 and 14 d. Calculation of apparent Michaelis constant (Kt) for both substrates indicated little change with age and thus the amount of carrier in the intestine may be increasing. Uptake capacity of the duodenum for glucose increased between hatch and 7 d of age but no changes were found between 7 and 14 d. In the jejunum, uptake capacity was constant from hatch to 14 d of age. In situ uptake of oleic acid in the duodenum did not change between hatch and 14 d of age. These results suggest that intestinal uptake capacity changes little after 7 d of age, and thus feed intake may be the major factor controlling nutrient uptake in chicks.