Effects of cereal and protein source on performance, apparent ileal protein digestibility and intestinal characteristics in weaner piglets.

Rye and rapeseed meal (RSM) are alternatives to wheat and soybean meal (SBM) in pig nutrition. The inclusion of rye and RSM instead of wheat and SBM may increase dietary fibre content in the feed, which may affect digestive physiology and intestinal function. However, research on the combined feeding of rye and RSM in piglets is still scarce. The aim of this study was to investigate the effects of rye and RSM containing feed on growth performance, protein and amino acid digestibility, physical characteristics of the digesta and the intestinal morphology in weaner piglets. A total of 88 piglets aged 28 d were randomly allotted to four different feeding groups at weaning: wheat/SBM, wheat/RSM, rye/SBM, rye/RSM. Cereals were included at 48%, SBM at 25% and RSM at 30%. Body weight gain and feed intake were recorded weekly. After 33 d, piglets were euthanised for assessment of digesta and intestinal morphology. Rye did not affect performance, whilst RSM resulted in reduced weight gain (p = 0.024) and feed intake (p = 0.037). Apparent ileal digestibility of crude protein and amino acids was decreased by rye and RSM (p < 0.05). Rye caused an acidification (p = 0.045) and increased viscosity (p = 0.013) of small intestinal digesta, a lower dry matter content of jejunal and colonic digesta (p < 0.05) and an increased relative weight of the colon tissue (p < 0.001). In conclusion, performance was not reduced when rye was used as an alternative to wheat in diets for weaner piglets. The inclusion of RSM instead of SBM to piglets' diet lowered animal performance under our conditions. Further investigations are warranted to characterise the quality of rapeseed meal and the optimum inclusion level in the diet for young pigs.

Lignocellulose as an insoluble fiber source in poultry nutrition: a review.

Extensive research in recent years into the use of various fiber sources in poultry nutrition has led to the perception that dietary fiber is more than a simple diet diluent. Several studies showed that the feeding of insoluble fiber sources such as oat hulls, sunflower hulls or wood shavings may affect digestive physiology and function improving chickens health and growth performance. In this context, the effect of lignocellulose as an insoluble dietary fiber source is increasingly being investigated. Lignocellulose is a component of plant cell walls and consists mainly of the insoluble carbohydrate polymers cellulose and hemicelluloses as well as the phenolic polymer lignin. Lignocellulose is chemically and physicochemically different from other insoluble fiber sources and thus possibly has different effects on poultry compared to traditional fiber sources. Several studies investigated the effect of dietary lignocellulose on growth performance, nutrient digestibility, gastrointestinal tract development and intestinal microbiota in broilers and laying hens. Studies differed in terms of feed formulation and lignocellulose inclusion level as well as products of different suppliers were used. The results obtained are inconsistent; beneficial, indifferent or detrimental effects of feeding lignocellulose were observed, so that a final assessment of lignocellulose as a "novel" insoluble fiber source is difficult. This review article summarizes the results of studies in connection with the feeding of lignocellulose to poultry, compares them with those that have used other insoluble fiber sources and illuminates the possible mechanisms of action.

Structure and age-dependent growth of the chicken liver together with liver fat quantification: A comparison between a dual-purpose and a broiler chicken line.

Rearing dual-purpose chickens is a practicable approach to avoid culling one-day-old male layer chicks. The present study examined the impact of a conventional fattening diet on the liver of a novel dual-purpose chicken line (Lohmann Dual, LD) in comparison to a broiler (Ross 308) chicken line. Age-related changes of structure and lipid content of the liver were assessed. One hundred twenty and newly hatched chicks (LD = 66, Ross = 54) were kept under the same husbandry conditions and fed a commercial diet for 5 weeks for Ross and 9 weeks for LD. Six birds of each line were examined weekly. Their body weight (BW) and liver mass were recorded. Microscopic structure and ultrastructure of the liver were investigated and the liver lipid content was measured using a pre-validated method. During the study period, liver mass increased with age, while normalized liver mass decreased. Furthermore, liver mass of Ross birds was greater than that of LD birds of the same BW. Overall, no significant differences were observed in the hepatic structure or ultrastructure between the two chicken lines. The hepatic lymphatic aggregations were without fibrous capsules and their number and area increased throughout the first week, then the values began to fluctuate with age in both chicken lines. The changes in the liver lipid content of the two chicken lines were within the normal physiological range over the term of the study. The liver lipid content correlated negatively with age and body weight in both lines. It was the highest on the first day then decreased until day 7 and thereafter did not change in both chicken lines. However, given the same body weight, the Ross chickens had a 9% greater liver lipid content than LD chickens. It is concluded that there is no apparent adverse effect of a high-energy diet on the liver of LD chickens.

Impact of an energy- and nutrient-reduced diet containing 10% lignocellulose on animal performance, body composition and egg quality of dual purpose laying hens.

In response to ethical concerns regarding the killing of day-old male chicks of layer breeds, the use of dual purpose chickens is increasingly discussed in public while data on nutritional requirements of dual purpose laying hens are not available. The present study examined the impact of an energy- and nutrient-reduced diet containing lignocellulose on performance, body composition and egg quality of dual purpose hens. Female Lohmann Dual chicks were allocated to 12 pens and fed two different diets for 52 weeks: a control (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose. During the trial, animal performance, whole-body composition and egg quality parameters of hens were consistently ascertained. The results showed that LC-fed hens had lower body weights compared to those receiving CON (p < 0.05). During the laying period, feed intake was increased in LC-fed hens (p < 0.001). LC-fed hens showed a higher egg production and egg mass resulting in an improved feed efficiency (p < 0.05) and laid smaller eggs compared to CON-fed hens (p < 0.001). At 52 weeks of age, bodies of LC-fed hens had higher protein and lower fat contents than those fed with CON diet (p ≤ 0.001). Mean body weight was positively correlated to the body fat content (p = 0.004) and body fat content was negatively correlated to the egg production (p = 0.043). Analyses of the egg quality showed that yolk mass at all sampling points and albumen mass at 27 and 42 weeks were lower in hens fed with diet LC compared to those fed with diet CON (p< 0.05). In conclusion, the feeding of energy- and nutrient-reduced diets containing 10% lignocellulose reduced the body fat content and simultaneously improved the laying performance in dual purpose hens.

Comparison of different histological protocols for the preservation and quantification of the intestinal mucus layer in pigs.

The histological characterization of the intestinal mucus layer is important for many scientific experiments investigating the interaction between intestinal microbiota, mucosal immune response and intestinal mucus production. The aim of this study was to examine and compare different fixation protocols for displaying and quantifying the intestinal mucus layer in piglets and to test which histomorphological parameters may correlate with the determined mucus layer thickness. Jejunal and colonal tissue samples of weaned piglets (n=10) were either frozen in liquid nitrogen or chemically fixed using methacarn solution. The frozen tissue samples were cryosectioned and subsequently postfixed using three different postfixatives: paraformaldehyde vapor, neutrally buffered formalin solution and ethanol solution. After dehydration, methacarn fixed tissues were embedded in paraffin wax. Both sections of cryopreserved and methacarn fixed tissue samples were stained with Alcian blue (AB)-PAS followed by the microscopically determination of the mucus layer thickness. Different pH values of the Alcian Blue staining solution and two mucus layer thickness measuring methods were compared. In addition, various histomorphological parameters of methacarn fixed tissue samples were evaluated including the number of goblet cells and the mucin staining area. Cryopreservation in combination with chemical postfixation led to mucus preservation in the colon of piglets allowing mucus thickness measurements. Mucus could be only partly preserved in cryosections of the jejunum impeding any quantitative description of the mucus layer thickness. The application of different postfixations, varying pH values of the AB solution and different mucus layer measuring methods led to comparable results regarding the mucus layer thickness. Methacarn fixation proved to be unsuitable for mucus depiction as only mucus patches were found in the jejunum or a detachment of the mucus layer from the epithelium was observed in the colon. Correlation analyses revealed that the proportion of the mucin staining area per crypt area (relative mucin staining) measured in methacarn fixed tissue samples corresponded to the colonal mucus layer thickness determined in cryopreserved tissue samples. In conclusion, the results showed that cryopreservation using liquid nitrogen followed by chemical postfixation and AB-PAS staining led to a reliable mucus preservation allowing a mucus thickness determination in the colon of pigs. Moreover, the detected relative mucin staining area may serve as a suitable histomorphological parameter for the assessment of the intestinal mucus layer thickness. The findings obtained in this study can be used for the implementation of an improved standard for the histological description of the mucus layer in the colon of pigs.

The effects of particle size, milling method, and thermal treatment of feed on performance, apparent ileal digestibility, and pH of the digesta in laying hens.

Various milling methods result in different particle size distributions and, in combination with mash and thermal treatment (expandate) of the feed, may have an impact on nutrient digestibility, pH of the digesta and subsequently the performance of an animal. Since this aspect has not been widely considered in laying hens, the objective of the present study was to investigate the effects of milling method, expansion, and particle size of feed on performance, apparent ileal nutrient digestibility, and pH of digesta in laying hens. Twelve variants of the same diet were produced. Four different milling techniques (hammer mill, roller mill, disc mill, and wedge-shaped disc mill) were used to grind the feed cereals. Coarse feed was obtained from all four mills. Additionally, fine feed was obtained from the hammer mill and the roller mill. Each of the six feed variants was offered as mash or expandate, resulting in a total of 12 treatments. The duration of the experimental period was 21 days. A total of 576 layers, each 19 weeks of age, were used in eight replicates. The statistical analysis for the four milling methods and two thermal treatments was performed using a 4×2 factorial arrangement. The effect of particle size was investigated using a 2×2×2 factorial arrangement including the coarse and fine particle sizes that were produced with the hammer mill and the roller mill as well as the mash and expandate. The animal performance and the pH of the digesta were not affected by the treatments. Ileal digestibility of starch was significantly improved by feeding mash compared to expandate (P=0.013) and by feeding coarse compared to fine feed (P=0.028). Based on this study, the tested milling methods can be used for the production of feed for laying hens without affecting performance and digestibility of nutrients.

Method for the preparation of mucosal flaps from the jejunum of laying hens for transporter studies in Ussing chambers.

Ussing chambers are frequently used for in vitro evaluation of intestinal transport physiology. The current study describes investigating the jejunal tissue from laying hens using a specific preparation method and evaluates the effect of glutamine in the maintenance buffer. Tunica mucosa was stripped from 104 jejunal samples from 10 hens and stabilised by a net device. Fifty samples were maintained with modified Krebs-Henseleit buffer (Control), 54 samples with additional 5 mM glutamine (Group Gln). The percentage of responding samples varied between 87 and 100%. Mean short circuit current (ΔI sc,) [µA/cm(2)] of samples exposed to 10 mM glucose in the Control group and Group Gln was 17.0 and 14.6 (p = 0.836), respectively, of samples exposed to 100 µM phloridzin -13.3 and -11.8 (p = 0.712), respectively, and of samples exposed to 100 µM carbachol 4.7 and 3.7 (p = 0.450), respectively. In conclusion, the net-supported method enabled a reliable investigation of jejunum from laying hens. Glutamine in the maintenance buffer was of no significant benefit.