S. E. Scheideler

A small variation in diet influences the Lactobacillus strain composition in the crop of broiler chickens

Feed composition has the potential to influence the activities of bacteria that colonize the digestive tract of broiler chickens with important consequences for animal health, well being, and food safety. In this study, the gut microbiota of two groups of broiler chickens raised in immediate vicinity but fed either a standard corn/soybean meal ration (corn-soy, CS) or a ration high in wheat middlings (high wheat, HW) was characterized. The findings revealed that this small variation in feed composition did not influence the distribution of microbial species present in the microbial community throughout the digestive tract. However, diet variation markedly influenced the Lactobacillus strain composition in the crop. Most striking, the dominant type in birds on the CS diet (Lactobacillus agilis type R5), which comprised 25% of the isolates, was not detected in birds fed the HW diet. The latter birds harbored a different strain of L. agilis (type R1) in a significantly higher ratio than birds on the CS diet. Several other strains were also specific to the particular diet. In conclusion, this study showed that a small variation in the composition of chicken feed that does not result in detectable differences in species composition can still have an impact on which microbial strains become dominant in the digestive tract. This finding has relevance in the application of probiotics and other direct-fed microbials in poultry husbandry.

Reproductive hormones, hepatic deiodinase messenger ribonucleic acid, and vasoactive intestinal polypeptide-immunoreactive cells in hypothalamus in the heat stress-induced or chemically induced hypothyroid laying hen

Heat stress (HS) effects on reproductive and thyroid hormones have been well documented; however, mechanisms of action are not well understood. Two studies were conducted to determine whether HS-induced and hypothyroid-induced effects are similar in the laying hen, with regard to reproductive hormones and vasoactive intestinal polypeptide (VIP)-immunoreactive cells in the hypothalamus. In study 1, thirty 32-wk-old Hy-Line W-36 laying hens, housed at 22 degrees C, were cannulated. On d 0 and then on d 1 to 5 of HS (35 degrees C, 50% RH), a daily blood sample was obtained and assayed for triiodothyronine (T(3)), thyroxine (T(4)), 17beta-estradiol (E(2)), progesterone (P(4)), prolactin (PRL), and VIP, and T(3):T(4)was calculated. On d 0, 1, 3, and 5, livers were obtained for hepatic type I deiodinase mRNA (cDI-1) determination. In study 2, eighty 32-wk-old hens were randomly assigned to 4 treatments of 20 birds each: 1) HS (36.5 degrees C, 50% RH), 2) thiouracil-induced hypothyroidism (HY), 3) HY + T(4) administration, and 4) control (22 degrees C). Beginning on d 1 of the 5-d study, daily blood samples (3.0 mL) were removed and assayed as in study 1. On d 5, brains were removed from 3 hens/treatment and immunoreactivity of VIP cells was determined. In study 1, HS reduced E(2), P(4), T(3) (P = 0.0001), T(3):T(4) ratio (P = 0.0078), and hepatic type I deiodinase mRNA (P = 0.0204) and increased T(4) (P = 0.0013); there was no effect on VIP or PRL. In study 2, HS and HY reduced T(3), T(3):T(4) ratio, and E(2) (P = 0.0001) and increased PRL (P = 0.0045); HS alone decreased P(4) (P = 0.0001). In HY + T(4), plasma E(2) and PRL were similar to control. Vasoactive intestinal polypeptide increased in plasma of HY birds, but there was no effect of HS or HY + T(4). Immunoreactive VIP cells increased (P = 0.0036) in nucleus inferior hypothalami of HS and HY brains. In HY + T(4), VIP immunoreactive cell numbers were similar to control. It appears that HY induced chemically or by HS exerts similar effects on reproductive hormones in the hen; the results suggest involvement of the VIP-PRL pathway even though peripheral blood concentrations were not consistent between studies.

The In Vivo Digestive Fate of the Cry3Bb1 Protein in Laying Hens Fed Diets Containing MON 863 Corn

Two trials were conducted to assess the fate of the Cry3Bb1 protein from YieldGard rootworm corn (MON 863) when fed to laying hens. In the first trial, 2 diets, 1 formulated with MON 863 and 1 with conventional corn, were fed to laying hens (12 replicate cages with 4 hens/cage per treatment) for 8 wk. Daily feed intake (FI), egg production (EP), and BW were measured. Prestudy fecal samples, wk 4 and 8 egg and fecal samples, and hepatic and pectoralis tissue samples were collected from 12 killed hens and were tested for the Cry3Bb1 protein. Corn source had no significant effects on FI, EP, or BW. Feces from hens fed diets containing MON 863 were positive for the Cry3Bb1 protein or proteolytic fragments (1.5 to 4.0 ppm fecal dry matter). The Cry3Bb1 protein could not be determined in eggs due to the presence of an interfering substance in all test and control eggs. No Cry3Bb1 protein was detected in hepatic and pectoralis tissue. In the second trial, the same test and control diets were fed to 12 hens each. Six hens/treatment were sampled after 7 and 28 d. Samples included blood, feces, and digesta (crop, small and large intestine, and ceca). The Cry3Bb1 protein could not be determined in blood due to the presence of an interfering substance in all test and control blood samples. The Cry3Bb1 protein or partially digested fragments, or both, were found in the digesta sampled from all sections of the digestive tract. About 98 to >99% of the dietary Cry3Bb1 protein was digested. Overall, MON 863, when fed to laying hens, had no significant effects on FI, EP, or BW. The Cry3Bb1 protein was extensively digested, similar to that of other dietary proteins, and was not detected in hepatic or muscle tissue.

Consumption of Omega-3 Fatty Acid-Enriched Eggs and Serum Lipids in Humans

ABSTRACT This study examined the effectiveness of consuming omega-3 fatty acid-enriched eggs (Omega Eggs) in increasing total dietary omega-3 fatty acids. Also examined was the impact of Omega Egg consumption on serum lipids. Sixteen hypercholesterolemic men and women with baseline serum total cholesterol concentrations of 5.17–7.76 mmol/L (200–300 mg/dL) followed the National Cholesterol Education Program Step I diet guidelines under the following conditions: (a) Step I diet without eggs, (b) Step I diet plus 12 regular eggs per week, and (c) Step I diet plus 12 Omega Eggs per week. The study design was a repeated 3X3 Latin square so that each subject received each of the three diet treatments. Consumption of Omega Eggs significantly increased omega-3 fatty acid intake (1.18 g/day) compared to consumption of regular eggs (0.71 g/day) or no eggs (0.81 g/day). The Omega Egg treatment did not significantly alter serum cholesterol or triacylglycerol concentration when all 16 subjects were included in the analysis. However, three subjects showed a significant increase in serum total cholesterol concentration when consuming regular eggs relative to no eggs. When these “responders” consumed Omega Eggs, serum total cholesterol concentration did not increase, despite a 3-fold increase in cholesterol intake relative to no egg treatment. These data suggest that Omega Eggs (12/week) can be included in the National Cholesterol Education Program Step I diet without increased serum total cholesterol or triacylglycerol concentration. In this way, the nutritional benefits of eggs could be realized without the detrimental effects of increased cholesterol intake.