Absorption Of Dietary Nutrients Research Articles

The Isolation of Flowing Mesenteric Lymph in Mice to Quantify In Vivo Kinetics of Dietary Lipid Absorption and Chylomicron Secretion.

Intestinal lipoproteins, especially triglyceride-rich chylomicrons, are a major driver of metabolism, inflammation, and cardiovascular diseases. However, isolating intestinal lipoproteins is very difficult in vivo because they are first secreted from the small intestine into the mesenteric lymphatics. Chylomicron-containing lymph then empties into the subclavian vein from the thoracic duct to deliver components of the meal to the heart, lungs, and, ultimately, whole-body circulation. Isolating naïve chylomicrons is impossible from blood since chylomicron triglyceride undergoes hydrolysis immediately upon interaction with lipoprotein lipase and other lipoprotein receptors in circulation. Therefore, the original 2-day lymph fistula procedure, described by Bollman et al. in rats, has historically been used to isolate fresh mesenteric lymph before its entry into the thoracic vein. That protocol has been improved upon and professionalized by the laboratory of Patrick Tso for the last 45 years, allowing for the analysis of these critical lipoproteins and secretions from the gut. The Tso lymph fistula procedure has now been updated and is presented here visually for the first time. This revised procedure is a single-day surgical technique for installing a duodenal feeding tube, cannulating the mesenteric lymph duct, and collecting lymph after a meal in conscious mice. The major benefits of these new techniques include the ability to reproducibly collect lymph from mice (which harnesses the power of genetic mouse models); the reduced anesthesia time for mice during the implantation of the duodenal infusion tube and the lymph cannula; the ability to continuously sample lymph throughout the feeding and post-prandial period; the ability to quantitatively measure hormones and cytokines before their dilution and enzymatic hydrolysis in blood; and the ability to collect large quantities of lymph for isolating intestinal lipoproteins. This technique is a powerful tool for directly and quantitatively measuring dietary nutrient absorption, intestinal lipoprotein synthesis, and chylomicron secretion.

The effect of the feed additive "Relikt A®" on the blood and milk parameters of newborn cows

This work is devoted to the study of the effect of the 4% feed additive "Relikt A®", which includes a complex of humic substances, on the morphological and biochemical parameters of blood, the physico-chemical composition of milk, namely, the content of milk protein, fat (their ratio), dry fat-free milk residue, density, acidity and conductivity. As a result of the studies on the 30th day, it was found that with the introduction of a 4% feed additive "Relict A®" into the diet at a dose of 200 mg/kg of live weight, the total protein in the blood serum of the experimental group exceeded the control values by 12,06% (pЈ0,01**), albumin - by 7,86% (рЈ0,05*), globulins - by 14,87% (рЈ0,01**), urea - by 21,33% (рЈ0,05*), calcium - by 17,41% (pЈ0.05*), calcium to phosphorus ratio - by 42,97% (pЈ0,001***), magnesium - by 8,14% relative to control values. According to the physicochemical analysis of milk after 14 days of the experiment, it was noted that the milk protein in the experimental group is higher than the control values by 8,00% (pЈ0,05*), the ratio of fat to protein is lower by 31,90% (pЈ0,05*). On the 30th day of the experiment, it was noted that the milk protein of the experimental group of animals is higher than the control ones by 8,36% (pЈ0,05*), SOMO (dry skimmed milk residue) - by 8,39% (pЈ0,05*), acidity is lower by 11,35% (рЈ0,01**). The introduction of the "Relikt A®" feed additive into the diet at a dose of 200 mg/kg optimizes the biochemical processes of the body of cows in the early period after calving, reduces the risk of ketosis and hypocalcaemia, and ensures the absorption of dietary nutrients, which is expressed in the corresponding physicochemical parameters of milk.

Lymphatic Connexins and Pannexins in Health and Disease.

This review highlights current knowledge on the expression and function of connexins and pannexins, transmembrane channel proteins that play an important role in intercellular communication, in both the developing and mature lymphatic vasculature. A particular focus is given to the involvement of these proteins in functions of the healthy lymphatic system. We describe their influence on the maintenance of extracellular fluid homeostasis, immune cell trafficking to draining lymph nodes and dietary nutrient absorption by intestinal villi. Moreover, new insights into connexin mutations in primary and secondary lymphedema as well as on the implication of lymphatic connexins and pannexins in acquired cardiovascular diseases are discussed, allowing for a better understanding of the role of these proteins in pathologies linked to dysfunctions in the lymphatic system.

A novel laxative method for crocodilians and digestibility of soybean (Glicine max) in broad-snouted caiman (Caiman latirostris)

The objectives of this study were to evaluate the laxative capacity of saline solution, vegetable oil, and a commercial drug on Caiman latirostris and determine digestibility of diets with plant derived protein sources as a supplement for this species. After a trial using three laxative treatments in different doses, caimans were treated with 1.5 mL of lactulose daily for two days. They were then force-fed their corresponding diet once per day for 7 days and then digesta residues were collected. Digestibility was determined through a dietary marker, acid digestion of digesta residues, and calculated with a standard equation. Digestion of diets were between 96 and 99%, exhibiting differences among these (P = 0.0006), with the control diet 2.45% lower than treatments diets (P = 0.0050). Digestibility of soybean meal was between 90 and 95%. There were differences according to the treatment diet (P = 0.018). The results of this study indicate that the use of lactulose as a laxative for C. latirostris is effective and does not affect health. Inclusion of soybean meal in the diet of C. latirostris at levels of 20–60% improved its digestibility and nutrients were efficiently digested. Deliberate ingestion of plant material by wild crocodilians may serve to aid digestion and absorption of dietary nutrients, and not act only as gastroliths. This information could be used to develop crocodilian diets and assist future research to determine optimum nutrient levels and ingredient combinations for farm-raised crocodilians fed compounded diets.

Effect of essential oils or saponins alone or in combination on productive performance, intestinal morphology and digestive enzymes' activity of broiler chickens.

This study was carried out to evaluate the effect of essential oils or saponins alone or in combination on productive performance, intestinal morphology, and digestive enzymes' activity in broilers. Four hundred one-day-old male broiler chickens were randomly assigned to four treatments, each with 5 replicates. The birds were fed experimental diets contained either no phytogenic feed additives (control) or were supplemented with 25.0mg/kg of an essential oil blend from star anise, rosemary, thyme and oregano (essential oils); 46.0mg/kg of a Quillaja saponin blend (saponins); or a combination of both phytogenic preparations (essential oils plus saponins). The experiment lasted for 42days. Body weight, feed intake and weight gain were recorded weekly, and the feed conversion ratio was calculated, throughout the experiment. Intestinal morphology and digestive enzymes' activity were determined at the end of the experiment. It was found that the body weight was increased by all dietary supplements at the end of the experiment. There was no change in performance parameters among the treatments during the starter period. At the grower period and the overall experiment, the weight gain of birds was higher in all supplemented groups compared to the control, but the feed conversion was better in the essential oils with saponins treatment. Supplementation of essential oils or saponins alone or in combination increased the villus height and the villus/crypt ratio of the intestine. There was an increase in trypsin, chymotrypsin and elastase activities in the essential oils plus saponins group only. The obtained results indicate that the phytogenic feed additives, especially essential oils with saponins, can be considered as new promising agents in promoting the growth performance of broilers. The effect could be related to its improving impact in intestinal development and increasing the protease enzymes' activity, resulting in increased protein digestibility and absorption of dietary nutrients.

Impact of preoperative fecal short chain fatty acids on postoperative infectious complications in esophageal cancer patients

BackgroundThe intestinal epithelial barrier allows absorption of dietary nutrients and prevents passage of pathogens and toxins into the body. Severe insults have a negative impact on the intestinal environment, which may decrease intestinal barrier function and cause bacterial translocation. Bacterial translocation, which can cause infectious complications, is defined as the passage of microbes from the gastrointestinal tract across the mucosal barrier to extraintestinal sites. The aim of this study was to investigate the correlation between concentrations of preoperative fecal organic acids and the occurrence of postoperative infectious complications in patients with esophageal cancer.MethodsFifty-five patients with esophageal cancer who underwent esophagectomy were enrolled in this study. Perioperative synbiotics were administered to all patients. Perioperative clinical characteristics and concentrations of preoperative fecal organic acids were compared between patients with and without postoperative infectious complications.ResultsPostoperative infectious complications occurred in 10 patients. In patients with complications, the concentrations of acetic acid and propionic acid were significantly lower than in patients without complications (p = 0.044 and 0.032, respectively). The concentration of butyric acid was nonsignificantly lower in patients with complications, while the concentration of lactic acid was nonsignificantly higher. The calculated gap between the concentrations of fecal acetic acid plus propionic acid plus butyric acid minus lactic acid was significantly lower in patients with complications. Multivariate analysis revealed that a low gap between acetic acid plus propionic acid plus butyric acid minus lactic acid was an independent risk factor for postoperative infectious complications (p = 0.027).ConclusionsPreoperative fecal concentrations of organic acids had a clinically important impact on the occurrence of postoperative infectious complications in patients with esophageal cancer. To reduce postoperative infectious complications, it may be useful to modulate the intestinal environment and maintain concentrations of fecal organic acids before surgery.

Intestinal inflammation induced by dextran sodium sulphate causes liver inflammation and lipid metabolism disfunction in laying hens

Gut inflammation caused by various factors including microbial infection leads to disorder of absorption of dietary nutrients and decrease in egg production in laying hens. We hypothesized that intestinal inflammation may affect egg production in laying hens through its impact on liver function. Dextran sodium sulphate (DSS) is known to induce intestinal inflammation in mammals, but whether it also induces inflammation in laying hens is not known. The goal of this study was to assess whether oral administration of DSS is a useful model of intestinal inflammation in laying hens and to characterize the effects of intestinal inflammation on egg production using this model. White Leghorn hens (350-day old) were administrated with or without 0.9 g of DSS/kg BW in drinking water for 5 D (n = 8, each). All laid eggs were collected, and their whole and eggshell weights were recorded. Blood was collected every day and used for biochemical analysis. Liver and intestinal tissues (duodenum, jejunum, ileum, cecum, cecal-tonsil, and colon) were collected 1 D after the final treatment. These tissue samples were used for histological analysis and PCR analysis. Oral administration of DSS in laying hens caused 1) histological disintegration of the cecal mucosal epithelium and increased monocyte/macrophage infiltration and IL-1β, IL-6, CXCLi2, IL-10, and TGFβ-4 gene expression; 2) decreased egg production; 3) increased leukocyte infiltration and IL-1β, CXCLi2, and IL-10 expression in association with a high frequency of lipopolysaccharide-positive cells in the liver; and 4) decreased expression of genes related to lipid synthesis, lipoprotein uptake, and yolk precursor production. These results suggested that oral administration of DSS is a useful method for inducing intestinal inflammation in laying hens, and intestinal inflammation may reduce egg production by disrupting egg yolk precursor production in association with liver inflammation.

Microbial nitrogen limitation in the mammalian large intestine.

Resource limitation is a fundamental factor governing the composition and function of ecological communities. However, the role of resource supply in structuring the intestinal microbiome has not been established and represents a challenge for mammals that rely on microbial symbionts for digestion: too little supply might starve the microbiome while too much supply might starve the host. Here, we present evidence that microbiota occupy a habitat limited in total nitrogen supply within the large intestines of 30 mammal species. Furthermore, lowering dietary protein levels in mice reduced bacterial fecal concentrations. A gradient of stoichiometry along the length of the gut was consistent with the hypothesis that intestinal nitrogen limitation results from host absorption of dietary nutrients. Nitrogen availability though is also likely shaped by host-microbe interactions: levels of host-secreted nitrogen were altered in germfree mice and when bacterial loads were reduced via experimental antibiotic treatment. Single-cell spectrometry revealed that members of the phylum Bacteroidetes consumed nitrogen in the large intestine more readily than other commensal taxa. Collectively, our findings support a model where nitrogen limitation arises from preferential host utilization of dietary nutrients, and we speculate that this resource limitation could enable hosts to regulate microbial communities in the large intestine. Furthermore, commensal microbiota may have adapted to nitrogen-limited settings, suggesting why excess dietary protein has been associated with degraded gut microbial ecosystems.

Zooming in on liver zonation.

Felmlee, Daniel J. Ph.D.1; Grün, Dominic Ph.D.2; Baumert, Thomas F. M.D3,4 Author Information

Determination of Histone 2B-Green Fluorescent Protein (GFP) Retention in Intestinal Stem Cells.

The epithelium of the gastrointestinal tract represents the interface between the luminal contents of the gut and that of the host tissues and plays a central role not only in regulating absorption of dietary nutrients but also in providing a barrier to prevent the entry of bacteria and other pathogens. Repair and replacement of damaged aging cells within the epithelium is modulated by stem cells, which are located in the intestinal crypts of the small intestine.Two distinct populations of intestinal stem cells have been described in the literature, one population at the very base of the crypt and a second population of long-lived stem cells located just above the Paneth cell zone. Herein, we describe a method to label this population of long-lived GFP label retaining cells. This method is free from confounding factors of previous methodologies based on radioactive tracers and also enables functional studies not previously possible using the radioactive tracer techniques described in the literature.

Diet, food components and the intestinal barrier

AbstractThe majority of dietary nutrient absorption occurs in the small intestine, with the intestinal epithelium acting as a barrier to the contents of the intestinal lumen. This barrier is maintained by intestinal epithelial cells, which support nutrient uptake but prevent translocation of bacteria, allergens and toxins. There is complex signalling and interaction between intestinal epithelia, macrophages, luminal contents and the microbiota which can modulate epithelial paracellular porosity. Intake of alcohol, fatty acids, pharmaceuticals and pathogenic bacteria has been reported to increase paracellular permeability, increase production of pro‐inflammatory cytokines and temporarily reorganise tight junctional proteins. Conversely, numerous probiotics, nutraceuticals and food‐derived bioactive components are promising due to reported restoration of intestinal barrier integrity by increasing production of anti‐inflammatory cytokines and increased expression of tight junctional proteins. In vitro co‐culture models exist and recent advances in microfluidic in vitro models are promising tools for investigating the complex effect of dietary components on the intestinal barrier. Temporarily perturbing the intestinal barrier may increase the oral bioavailability of therapeutic molecules. However, people with impaired intestinal integrity (e.g. those with Crohn's, coeliac or ulcerative colitis disease) should avoid foods which further perturb barrier integrity, while increasing intake of specific foods and possibly probiotics to promote intestinal barrier restoration.

Progress and prospect of lymphangiogenesis research

During the last twenty years, we have witnessed a rapid progress in the field of lymphatic vascular biology. The increase of lymphatic research has greatly deepened our understanding of the lymphatic system in health as well as in diseases. This review starts with the description of the current understanding of the mechanism underlying lymphatic formation and remodeling in development. In mammals, lymphatic vessel development initiates with the specification of lymphatic endothelial cells from a population of venous endothelial cells in the lateral parts of the anterior cardinal veins. This is followed by the formation of lymph sacs, which undergoes expansion into the primitive lymphatic plexus by the process of lymphangiogenesis. The primary lymphatic network is further remodeled into a mature lymphatic system composed of lymphatic capillaries and collecting lymphatics containing intraluminal valves as well as smooth muscle cell coverage. Several key factors and pathways have been identified to participate in the process, including lymphangiogenic growth factors and receptors, extracellular matrix proteins and cell junction molecules, intracellular signal mediators and transcription factors. It is interesting to find out how these factors coordinate to control collecting vessel formation and maturation, and whether they work in the same pathway or in different pathways controlling specific cellular programs. Secondly, the authors summarize the physiological functions of lymphatic system, including the essential role of lymphatic system in the maintenance of tissue fluid homeostasis. Defective lymphatic development or damage of the lymphatic system resulting from surgery or infection leads to lymphedema. In immune system, lymphatic vessels are crucial for the leukocyte trafficking from peripheral tissues to their draining lymph nodes and for the drainage of soluble antigens. Furthermore, the absorption of dietary nutrients is critically dependent on the lymphatic vessels in intestines, also known as lacteals in intestinal villi. Finally, the authors have discussed the involvement of lymphatic system in several diseases including tumor metastasis, inflammation and cardiovascular diseases. It has also been well established that tumor associated lymphangiogenesis promotes lymphogenous tumor metastasis. Although the molecular players responsible for lymphatic vessel growth is similar in development and tumor, there are distinct characteristics of tumor-associated lymphangiogenesis, including the lack of lymphangiogenic growth factor gradient in tumor. Therefore, tumor-associated lymphatics are patchy, disorganized without a hierarchical vascular pattern, and also not homogenously distributed within tumors. In addition, inflammation is often associated with profound lymphatic vessel growth and remodeling, and there are also evidence showing that the abnormal lymphatic growth is implicated in cardiovascular diseases. In spite of the recent progress in the research field of lymph-vascular biology, there is still lack of effective drugs for the prevention and treatment of lymphedema and lymphatic related diseases. Thus, continued support and further increase in research investment in this field are very much wanted to better understand the cellular events and molecular players involved in lymphatic vessel growth and function at both physiological and pathological conditions.

The Impact of Gastric Atrophy on the Incidence of Diabetes

Gastric atrophy results in lower plasma ghrelin, higher gastrin secretion, a change in gut microbiota, and altered dietary nutrient absorption, which may be associated with the incidence of diabetes. Helicobacter pylori (H. pylori) infection is a major cause of gastric atrophy and is associated with diabetes in some reports. Since there is no study which investigates the impact of gastric atrophy on diabetes, we conduct a prospective cohort study to examine the relationship between H. pylori infection, gastric atrophy, and incident diabetes. In this study, subjects with gastric atrophy had a lower risk of incident diabetes, compared to those without gastric atrophy. The extent of gastric atrophy, measured by serum pepsinogen (PG) I/II ratio, was correlated with age, H. pylori IgG titer, HOMA2-IR, and HOMA2%B. When gastric atrophy is more extensive, presented as a lower serum PG I/II ratio, the risk of incident diabetes is lower. On the other hand, there was no significant association between H. pylori infection and the incidence of diabetes. In conclusion, the presence and the extent of gastric atrophy, but not H. pylori infection, are associated with incident diabetes. Further studies are needed to investigate the detailed mechanisms and the potential applications of the findings to guide diabetes screening and treatment strategies.

L-Theanine Administration Modulates the Absorption of Dietary Nutrients and Expression of Transporters and Receptors in the Intestinal Mucosa of Rats.

L-theanine has various advantageous functions for human health; whether or not it could mediate the nutrients absorption is unknown yet. The effects of L-theanine on intestinal nutrients absorption were investigated using rats ingesting L-theanine solution (0, 50, 200, and 400 mg/kg body weight) per day for two weeks. The decline of insulin secretion and glucose concentration in the serum was observed by L-theanine. Urea and high-density lipoprotein were also reduced by 50 mg/kg L-theanine. Jejunal and ileac basic amino acids transporters SLC7a1 and SLC7a9, neutral SLC1a5 and SLC16a10, and acidic SLC1a1 expression were upregulated. The expression of intestinal SGLT3 and GLUT5 responsible for carbohydrates uptake and GPR120 and FABP2 associated with fatty acids transport were inhibited. These results indicated that L-theanine could inhibit the glucose uptake by downregulating the related gene expression in the small intestine of rats. Intestinal gene expression of transporters responding to amino acids absorption was stimulated by L-theanine administration.

Effects of dietary NaCl on the in vivo apparent absorption of dietary nutrients determined in rainbow trout (Oncorhynchus mykiss)

Rainbow trout (mean body weight 52.3g) were reared in freshwater and fed a semi-purified low-sodium (Na) diet (Na content 0.027%) or NaCl-supplemented diets (Na content 0.35% and 1.75%). The chyme of the proximal and distal intestines of fish were collected by dissection. The diets and chyme were analyzed, and apparent digestibility (net absorption) and indigestibility of dietary nutrients was estimated based on yttrium as a reference. Na concentration of the intestinal chyme, both proximal and distal regions, was similar regardless of dietary Na levels. A major Na secretion into the proximal lumen was noted in fish fed the low-Na diet. The net phosphorus (P) absorption was already ~90% at the proximal intestine, but dietary Na had no detectable effect on net P absorption, both in the proximal and distal intestine. The Ca content was more than two times higher in the distal than the proximal chyme. Dietary Na had no effect on chyme Ca content, but tended to increase Mg content in the proximal and distal chyme. There was no apparent effect of dietary Na on net Fe and Zn absorption in the proximal and distal intestine. Dietary Na decreased net absorption of Mn. Dietary Na tended to increase dry matter and organic carbon digestibilities in the distal intestine. Digestibility of crude protein (CP) was increased by dietary Na in the proximal, but not distal, region. These results collectively indicate that dietary Na may slightly increase digestibilities of macronutrients in rainbow trout reared in freshwater. Statement of relevanceSodium (Na) is an important ion for dietary nutrient absorption in the intestine. However, the effect of dietary Na on an in vivo nutrient absorption efficiency has been little studied in fish. Hence, we evaluated the effect of dietary NaCl on nutrient digestibility (absorption) in rainbow trout reared in freshwater.

Molecular detection of chicken parvovirus in broilers with enteric disorders presenting curving of duodenal loop, pancreatic atrophy, and mesenteritis

Enteric disorders are an important cause of economic losses in broiler chickens worldwide. Several agents have been associated with enteric problems, such as viruses, bacteria, and parasites. In this study, broiler chickens showing signs of enteric disorders were subjected to molecular diagnosis for several viral agents and also for pathological examination for elucidating this problem. Thus, the chickens were screened for avian nephritis virus (ANV), chicken astrovirus (CAstV), avian rotavirus (ArtV), avian reovirus (AReoV), infectious bronchitis virus (IBV), fowl adenovirus group I (FAdV-1), and chicken parvovirus (ChPV). Postmortem examinations revealed a curving of the duodenal loop (J-like appearance) and intestines filled with liquid and gaseous content. Histopathological analysis of the duodenal loop showed pancreatic atrophy, acute mesenteritis, and enteritis. PCR results showed that ChPV was the sole viral agent detected in samples with lesions such as the curved duodenal loop and pancreatic atrophy. Molecular characterization of the nucleotide and deduced amino acid sequences revealed a high similarity with other strains of ChPV from Brazil, Canada, United States, Europe, and Asia. These findings suggest an association between ChPV and the development of enteritis, pancreatitis, and pancreatic atrophy, which may lead to curling of the duodenal loop. Together, these alterations may disrupt the normal functioning of the digestive system, diminishing digestion and the absorption of dietary nutrients and consequently leading to reduced weight gain, flock impairment, dwarfism, and an elevated feed conversion rate.

초이사료 배합설계를 통한 육계 생산성 증대방안

본 총설은 부화 후 1주일간 급여되는 초이사료 적용의 필요성 및 배합설계방안을 제시하여 육계생산성을 증대하는 방안을 살펴보고자 한다. 육계는 지난 수년 간 괄목할 만한 증체 속도 증가, 출하일령 단축 그리고 사료효율 향상을 보 여줬다. 이는 육종 개량, 사육 환경 개선, 과학적인 사양관리기법 적용 및 적정 영양공급 등의 결과이며, 한국의 경우 다른 나라에 비해 육계사육기간이 매우 짧아, 부화 후 약 31일령이면 출하가 이루어지고 있는 실정이다. 따라서 육계초기 1주일간은 전체 사육기간의 20% 이상을 차지할 뿐만 아니라, 초기성장이 출하체중과 일령 그리고 사료효율에 지대한 영향을 미치고 있으므로 초기 1주일간의 사료공급을 통한 생산성 향상이 매우 중요하다. 생후 7일령까지의 어린 병아리는 소화기관 미발달과 효소의 분비 및 활력 부족으로 사료 내 영양소의 소화 흡수 및 이용률이 낮은 편임을 고려하여, 초이사료의 급여를 위한 영양적 접근 방법으로는 크게 3가지로 나눌 수 있다. 첫 번째로는 단순히 영양수준을 올리기보다는 양질의 원료 사용, 특히 단백질과 탄수화물 이용률 증진을 위 한 선택적인 원료 사용 및 원료의 가공처리가 필요하다. 에너지 공급의 경우, 에너지 수준 못지않게 에너지 공급원이 중요한데, 특히 불포화지방산공급원인 식물성이 기름 첨가를 권장한다. 영양소 공급의 경우, 단백질 함량을 증가시키기보다는 이상적 아미노산 비율에 따른 필수아미노산 공급이 중요하다. 필요 시 효소제를 비롯한 항생제 등의 대체 물질 첨가를 통해 항병력이나 소화흡수율을 향상시키는 방안을 고려해 볼 수 있다. 아울러 기타 제한 아미노산의 충족에 대한 연구와 부화 후 7일간 사료 내 전해질 균형의 영향에 대한 연구가 앞으로 필요하다. There are approximately 1,500 broiler farms in Korea, each raising 55,000 birds. Ninety-five percent of the farms are contracted with Integration Company. According to the Korean broiler performance index, broilers in Korea are marketed at 32 days with 1.52 kg of body weight. In contrast, the market age and body weight of broilers are 47 days/2.8 kg in the United States and 42 days/2.5 kg in Europe. Because of the younger market age of the Korean broiler, the pre-starter feed is important. Chicks exhibit poor absorption of dietary nutrients up to 7 days after hatching due to an immature digestive system and low enzyme secretion rate and activity. At the beginning of hatching, chicks obtain their nutrients from the egg yolk sac. It is highly recommended that chicks, after consuming the nutrients in the egg yolk sac, are given supplemented pre-starter feed to increase early growth rates and improve the performance of broiler production. Pre-starter nutrient requirements are not expressed in NRC, so Korean feeding standards for poultry and commercial breeding companies determine the nutrient requirements of pre-starter broiler chickens. Three approaches are followed to formulate specially designed pre-starter feeds for broiler chicks: (i) selective use of raw materials, (ii) proper standards of nutrient supply, and (iii) application of feed additives such as exogenous enzymes. In the selection of raw materials, those with high digestibility can be used. The absorption rate of carbohydrates in grains can be increased through feed processing at high temperature and high pressure. Soy proteins and fish meal can also be added as protein sources. As an energy source, vegetable oils are preferred over animal fats because of the former's high digestibility. It is suggested that the levels of proteins and amino acids are higher in pre-starter feed than in starter feed. With regard to energy, the sources of energy are more important than the levels of energy in feed. Feed additives such as exogenous enzymes can be used to improve nutrient digestibility. In addition, organic acids and plant extracts can be used as alternatives to animal growth promoters to stimulate immunity and prevent diseases. The growth performance of broilers is affected by various factors, such as management and disease control, in addition to the nutritional strategy; however, nutritional strategies play an important role in improving the productivity of broilers. Therefore, nutritional strategies, along with management and disease control, are required for improving the productivity of broilers in Korea.

Elemental mapping of the entire intact Drosophila gastrointestinal tract.

The main role of the animal gastrointestinal (GI) tract is the selective absorption of dietary nutrients from ingested food sources. One class of vital micronutrients are the essential biometals such as copper, zinc and iron, which participate in a plethora of biological process, acting as enzymatic or structural co-factors for numerous proteins and also as important cellular signalling molecules. To help elucidate the mechanisms by which biometals are absorbed from the diet, we mapped elemental distribution in entire, intact Drosophila larval GI tracts using synchrotron X-ray fluorescence microscopy. Our results revealed distinct regions of the GI tract enriched for specific metals. Copper was found to be concentrated in the copper cell region but also in the region directly anterior to the copper cells and unexpectedly, in the middle midgut/iron cell region as well. Iron was observed exclusively in the iron cell region, confirming previous work with iron-specific histological stains. Zinc was observed throughout the GI tract with an increased accumulation in the posterior midgut region, while manganese was seen to co-localize with calcium specifically in clusters in the distal Malpighian tubules. This work simultaneously reveals distribution of a number of biologically important elements in entire, intact GI tracts. These distributions revealed not only a previously undescribed Ca/Mn co-localization, but also the unexpected presence of additional Cu accumulations in the iron cell region.

Dietary essentiality of "nutritionally non-essential amino acids" for animals and humans.

Based on growth or nitrogen balance, amino acids (AA) had traditionally been classified as nutritionally essential (indispensable) or non-essential (dispensable) for animals and humans. Nutritionally essential AA (EAA) are defined as either those AA whose carbon skeletons cannot be synthesized de novo in animal cells or those that normally are insufficiently synthesized de novo by the animal organism relative to its needs for maintenance, growth, development, and health and which must be provided in the diet to meet requirements. In contrast, nutritionally non-essential AA (NEAA) are those AA which can be synthesized de novo in adequate amounts by the animal organism to meet requirements for maintenance, growth, development, and health and, therefore, need not be provided in the diet. Although EAA and NEAA had been described for over a century, there are no compelling data to substantiate the assumption that NEAA are synthesized sufficiently in animals and humans to meet the needs for maximal growth and optimal health. NEAA play important roles in regulating gene expression, cell signaling pathways, digestion and absorption of dietary nutrients, DNA and protein synthesis, proteolysis, metabolism of glucose and lipids, endocrine status, men and women fertility, acid-base balance, antioxidative responses, detoxification of xenobiotics and endogenous metabolites, neurotransmission, and immunity. Emerging evidence indicates dietary essentiality of "nutritionally non-essential amino acids" for animals and humans to achieve their full genetic potential for growth, development, reproduction, lactation, and resistance to metabolic and infectious diseases. This concept represents a new paradigm shift in protein nutrition to guide the feeding of mammals (including livestock), poultry, and fish.

Protein source and nutrient density in the diets of male broilers from 8 to 21 d of age: Effects on small intestine morphology

In a companion study, high amino acid (AA) or apparent metabolizable energy (AME) densities in the diets of broilers from 8 to 21 d of age were found to improve feed conversion. A total of 1,120 male Ross × Ross 708 chicks were randomly allocated to 80 pens (8 treatments, 10 replications per treatment, 14 chicks per pen). A 2 × 2 × 2 factorial arrangement of treatments was used to investigate the interaction among the protein source (high distillers dried grains with solubles diet [hDDGS] or high meat and bone meal diet [hMBM]), AA density (moderate or high), and AME density (2,998 or 3,100 kcal/kg) of diets on small intestine morphology. Duodenum, jejunum, and ileum samples from 2 chicks per pen were collected and measured individually at 21 d. Jejunum sections were processed for histological analysis. Chicks fed hDDGS diets exhibited longer small intestines than did chicks fed hMBM diets. Particularly, when chicks were fed high AA density diets, jejuna were longer in groups fed hDDGS diets than groups fed hMBM diets. Dietary treatments did not affect jejunum villus height, width, area, crypt depth, villus to crypt ratio, goblet cell size, or cell density. In birds fed diets containing a moderate AA and a high AME density, jejunum muscle layers of chicks fed hDDGS diets were thicker than those fed hMBM diets. Chicks exhibited a lower feed conversion ratio (FCR) and a higher BW gain when their crypts were shorter. In conclusion, an hDDGS diet may facilitate small intestine longitudinal growth in broilers, which may subsequently improve dietary nutrient absorption. In addition, broiler chicks with shallow intestinal crypts exhibited better growth performance.