In ovo peptide YY administration improves growth and feed conversion ratios in week-old broiler chicks

Pancreatic PYY but not PPY expression is responsive to short-term nutritional state and the pancreas constitutes the major site of PYY mRNA expression in chickens

PP-fold peptides such as peptide YY (PYY) and pancreatic polypeptide (PPY) are known to play key roles in vertebrate energy homeostasis. Until recently, no gene sequence was available for avian PYY and therefore a gap in knowledge of regulation of its expression exists in avian species. Here we further evidence the mRNA sequence for chicken PYY and show that the pancreas is the major site of its mRNA expression, with a secondary peak of expression around the distal jejunum, in contrast to mammals where the large intestine is the major site of PYY expression. We also demonstrate that pancreatic PYY expression is responsive to short-term and long-term nutritional state, increasing within hours of feeding, in contrast to intestinal PYY which does not fluctuate to the same extent, and pancreatic PPY which appears to be primarily determined by long-term energy state. Both pancreatic PYY and PPY expression were found to exhibit ontogeny, being evenly distributed throughout the pancreas in young (2wk) chicks but having a decreasing splenic to duodenal gradient by adolescence (12wk).

Prospects of in ovo feeding and nutrient supplementation for poultry: the science and commercial applications--a review

In ovo supplementation of poultry embryos was first reported several decades ago, but it is only recently that concerted research has been directed at developing the technology for this process to be routinely used by the poultry industry. Although the technology of in ovo feeding was patented more than 10 years ago, it has not been widely adopted by the poultry industry. This review examines the early development of the enteric system of the poultry embryo; defines and distinguishes between in ovo feeding and in ovo nutrient administration; highlights the importance of early feeding of the chick; and discusses the development of in ovo feeding technology and its effects on hatchability, growth, gut health and immune response of chicks. The range of possible nutrients that can be administered is also explored. The limitations associated with embryo development and nutrient metabolism are highlighted, leading to the prediction of the future role of in ovo feeding in the poultry industry.

High levels of dietary carbohydrate increase glucose transport in poult intestine

The hypothesis was proposed that the carbohydrate in the first diet fed to turkey hatchlings upregulates the glucose transport system. Heavy and light body mass poults were observed to determine differences in glucose transport and carbohydrate digestion. Poults were weighed immediately posthatching. Heavy poults were at least +/-2 S.D. above the mean whereas light poults were at least +/-S.D. below the population mean (62.5 +/- 0.4). Each group was randomly assigned to one of two diets. One diet contained 50% carbohydrate and the remaining diet had 15% carbohydrate. Although the diets were isocaloric, differing carbohydrate (corn starch) and fat (cottonseed oil) content had significant effects on body masses within 3 days. Poults fed low carbohydrate weighed more than those on high carbohydrate perhaps because fat is a preferred energy substrate in the neonatal turkey. Greater carbohydrate in the diet increased glucose uptake and maltase activity compared to diets containing more fat. Heavier poults at hatching remained heavier at 3 days posthatching. No differences between body mass categories were noted in glucose uptake measurements. Thus, differences seen in growth rates may not be attributed to glucose transport in the jejunum. It is concluded that turkeys belong to the class of birds in which the poults respond to more carbohydrate in the diet by increasing plasma T(3) concentrations, upregulating the glucose transport system, and increasing enzymatic activity as with maltase.

Administration of triiodothyronine and dopamine to broiler chicks increases growth, feed conversion and visceral organ mass

The influences of triiodothyronine (T3) or dopamine (DA) administration on growth, feed conversion, and visceral weights in broiler chicks between the ages of 6 and 12 d posthatch were investigated. In Trial 1, six chicks at age 6 d were randomly administered one of the following treatments: 0.37, 0.74, 1.48, and 2.96 micromol T3/kg BW or 0.07, 0.14, 0.28, and 0.56 micromol DA/kg BW. Both T3 and DA were administered via intraperitoneal injections between the end of sternum and the ends of os pubis, with 0.9% saline as the excepient. In addition, two groups of six birds each were either not injected or injected with excepient only, as controls. Four replications were carried out with a total of 264 chicks. Heart weight as a percentage of feed-deprived body weight (FDBW) of the chicks injected with 2.96 micromol T3/kg BW was heavier than that of controls. Other variables measured were not significantly different between treatments. In trial 2, six chicks at age 6 d were randomly administered, one of the following treatments: 0.56, 1.12, 2.24, and 4.48 micromol T3/kg diet or 0.40, 0.80, 1.60, and 3.20 micromol DA/kg diet as well as a nonsupplemented control. Four replications were carried out with 216 chicks. The results in Trial 2 showed that the effects of T3 (X, micromol/kg diet) on body weight gain (Y1, g) and feed consumption (Y2, g) were linear (Y1 = 310 - 21.5X, R2 = 0.868, P < 0.001 and Y2 = 398 - 22.3X, R2 = 0.765, P < 0.001, respectively). The feed conversion ratio, the weight of liver, the weights of various intestinal segments, the lengths of the duodenum, jejunum and the ileum, as well as weight per centimeter jejunal length, gizzard weight as percentage of FDBW, and the duodenal length per kilogram FDBW all had linear responses (P < 0.05) to the level of dietary supplementation of T3. The effect of dietary supplementation of T3 on the heart weight was quadratic (Y16 = 2.58 + 0.89X - 0.17 X2, R2 = 0.526, P < 0.01). Similarly, the weights of pancreas and gizzard, the heart weight as a percentage of FDBW and the pancreas weight as a percentage of FDBW all had second-order curve responses. Dietary DA supplementation exerted no effect on the variables measured except that the regression of the heart weight as a percentage of FDBW on dietary DA supplementation (X1, micromol/kg diet) existed, namely, Z1 = 0.64 + 0.24 X1 - 0.23 X1(2) + 0.05 X1(3) (R2 = 0.868, P < 0.05).

In ovo peptide YY and epidermal growth factor administration and their effects on growth and yolk utilization in neonatal meat-type chickens (Gallus domesticus)

The effects of in ovo peptide YY (PYY) or epidermal growth factor (EGF) administration on chick growth, yolk absorption and yolk stalk function in posthatch (0-5 days) meat-type or broiler chicks were determined. At Day 18 of incubation, treated eggs were injected into the air cell with 100 microl of either PYY (Trial 1) or EGF (Trial 2) at a dosage of 600 microg/kg egg weight. Saline-treated control eggs were injected similarly with 0.9% saline. At hatch, 200 microl of (51)Cr-labeled microspheres were injected into chick yolk sacs. Epidermal growth factor increased ileal wet weight adjusted for body weight as well as ileal serosal dry matter. Body weight, feed consumption and excreta weight per bird, and relative weights of the yolk sac, intestine and liver were significantly affected by age of the chick in both trials. Relative radioactivity of the yolk sac, yolk stalk, blood, liver, and kidneys were affected by bird age in Trial 2; however, there were no significant effects due to PYY or EGF treatments on relative radioactivity of the tissues and organs examined. These data suggest that PYY and EGF had no effect on yolk absorption or yolk stalk function through 5 days in the posthatch chick.

Neuropeptide Y, peptide YY and aluminum in Alzheimer's disease: is there an etiological relationship?

Neuropeptide Y (NPY) and peptide YY (PYY) are members of the pancreatic polypeptide family which have a high degree of primary and tertiary structural homology. They function as neurotransmitters and humoral agents in central nervous system and gastrointestinal function. During the last two decades, NPY body fluid concentrations and NPY/PYY brain receptor numbers have been demonstrated to be altered during the course of Alzheimer's disease. Recent research has shown that both NPY and PYY may be involved in aluminum metabolism in animal models. A brief discussion of the structure, biological activity and possible involvement of these peptides in aluminum metabolism and Alzheimer's disease is contained herein.