Citrus Extract Improves the Absorption and Utilization of Nitrogen and Gut Health of Piglets

Abstract

The purpose of this study was to investigate the effects of citrus extract (CE) on plasma free amino acids, intestinal morphology and enzymes activity, fecal nitrogen and phosphorus emissions in piglets. The experiment was performed on 144 weaned piglets (Duroc × Landrace × Large White) divided into three groups. Control (CON), fed a basic diet; Antibiotic (ANTI), fed a basic diet supplemented with 75 g/t chlortetracycline; Citrus extract (CE), fed a basic diet supplemented with 300 mL/t CE. The albumin content of the CE group was significantly higher than the CON group. Compared with the CON and ANTI groups, the CE group had increased concentrations of plasma total essential amino acids and threonine. Compared with the CON group, CE increased the α-aminoadipic acid concentration, while compared with ANTI group, it increased the 3-methylhistidine concentration. Compared with the CON group, the crypt depth of duodenum, jejunum and ileum decreased, and the ratio of villus height to crypt depth of ileum increased in the ANTI and CE groups. CE increased the activity of alkaline phosphatase and lipase in duodenum, and the activity of alkaline phosphatase and trypsin in jejunum. In brief, CE improved the absorption and utilization of nitrogen, intestinal morphology and digestive enzymes activity.

Dietary supplementation with citrus extract alters the plasma parameters, circulating amino acid profiles and gene expression of small intestinal nutrient transporters in Chinese yellow‐feathered broilers

“…Therefore, it is reasonable to suggest that the CE‐induced increase of plasma glucose may partly explain the increase of the growth performance by CE treatment. In addition, dietary CE supplementation also affected urea metabolism in broilers, as indicated by the decreased plasma urea concentration, which is consistent with a previous study, which also found CE decreased urea concentration in weanling piglets fed a CE‐supplemented diet 20 . Blood urea is the main end‐product of AA catabolism in the host, and urea concentration is recognized as an indicator of the protein requirement and AA utilization 43 .…”

“…The current study found that dietary supplementation with CE significantly increased plasma total protein, albumin and glucose concentrations. Previous studies reported similar findings indicating that dietary supplementation with CE increased serum total protein concentration in broilers 4 and plasma albumin concentration in weanling piglets 20 . Liver is the main source of blood proteins, and dietary AAs are the preferred precursor for hepatic protein synthesis in animals 40 .…”

“…Dietary supplementation with CE significantly changed the AA profile in plasma, including increasing essential AA content, such as isoleucine, leucine, lysine, methionine and valine. In weanling piglets, a previous study also found that CE treatment increased plasma essential AA content 20 . Blood is the major AA circulating pool and plasma free AAs are the metabolic intermediates for protein nitrogenous anabolism and catabolism 16 .…”

“…The morphological structure of the small intestine plays an important role in nutrient absorption and digestion, and the villus height, crypt depth and V/C ratio are the key indicators reflecting the state of intestinal structure and function 51,52 . A previous study indicated that CE treatment decreased the jejunal and ileal crypt depth, but increased the ileal V/C ratio in weanling piglets 20 . Similarly, this study also found that CE significantly increased the villus height in the ileum, and jejunal and ileal V/C ratio, but decreased the jejunal and ileal crypt depth.…”

“…Plasma biochemical parameters and intestinal integrity reflect physiological conditions and nutritional absorption function state in animals 19 . In weanling piglets, previous studies have found that dietary supplementation with CE significantly increased the serum concentration of essential AAs and albumin, while decreasing urea concentration 20 . Additionally, it has been shown that some plant extracts can also modulate the expression of AA transport proteins in the intestine of livestock and poultry 21–23 .…”