Interactive effect of dietary protein and dried citrus pulp levels on growth performance, small intestinal morphology, and hindgut fermentation of weanling pigs1

Abstract

Weanling pigs ( = 108, 21 d of age, 5.82 ± 0.16 kg initial BW) were assigned to a 2 × 2 factorial arrangement of treatments to evaluate the effects of dietary levels of CP (high- and low-CP diets) and dried citrus pulp (DCP; 0% and 7.5%) on growth performance, small intestinal morphology, and hindgut fermentation. Pigs were blocked by initial BW and allotted to 1 of 9 pens, each containing 3 pigs. The high-CP diets consisted of feeding 20% and 21% CP levels throughout phase 1 (0 to 14 d) and phase 2 (14 to 28 d), respectively. For the low-CP diets, CP levels were reduced by 4% units as compared with the high-CP diets in both phases. Crystalline AA were supplied to maintain an ideal AA pattern. Pig BW and pen feed disappearance were recorded weekly. On d 7 and 28 postweaning, 1 pig from each pen was euthanized for collection of small intestinal tissues and digesta from cecum and colon. There were no CP × DCP interactions for growth performance and gut morphology. Although the low-CP diet decreased ADG ( = 0.03) and G:F ( = 0.02) from d 21 to 28 postweaning, overall performance was unaffected by the treatments. On d 7 postweaning, pigs fed the low-CP diet tended to have increased ( = 0.09) crypt depth in the duodenum. Low-CP diets tended to increase ( = 0.06) crypt depth and reduce ( = 0.08) villus:crypt ratio in the jejunum on d 7. Dietary treatments did not affect ileal morphology. On d 7 postweaning, low-CP diets tended to reduce ( = 0.09) cecal total VFA, whereas dietary DCP inclusion tended to decrease ( = 0.07) colonic propionate. Including 7.5% DCP to the diet decreased ( < 0.05) colonic isovalerate and ammonia N concentrations on d 7 only for pigs fed the low-CP diet. On d 28 postweaning, DCP inclusion in low-CP diets decreased ( < 0.05) butyrate, isovalerate, and valerate concentrations in the cecum, as well as isovalerate, valerate, and ammonia N concentrations in the colon. Including 7.5% DCP to the diet increased ( < 0.05) acetate:propionate ratio in the hindgut on both d 7 and 28 postweaning only for pigs fed the high-CP diet. Lactate concentration was unaffected by the treatments. These results indicate that feeding low-CP AA-supplemented diets did not compromise overall growth performance, but slightly increased damage in the gut morphology of weanling pigs. Moreover, adding 7.5% DCP to low-CP AA-supplemented diets shifted the fermentation pattern in the hindgut of weanling pigs by decreasing protein fermentation metabolites.

Intestinal Health and Threonine Requirement of Growing Pigs Fed Diets Containing High Dietary Fibre and Fermentable Protein

“…For example, previous work in pigs showed that when DF is included in high protein diets, protein fermentation and production of harmful metabolites is reduced and there is increased production of beneficial metabolites, such as acetic acid, butyric acid, and propionic acid [14]. Moreover, highly fermentable sources of DF, such as sugar beet pulp, can provide intestinal microbes an alternative, and potentially preferred, source of substrate for fermentation, allowing for the incorporation of N into the microbial biomass, further reducing the concentration of harmful fermentation metabolites (e.g., BCFA, ammonia) [25,26].…”

“…Other studies have reported similar effects of high protein diets on digesta ammonia and other biogenic amine (putrescine, spermidine, spermine etc.) concentrations in the gut and the counteracting effect of the addition of a high fibre source [1,25]. Digesta SCFA and BCFA are considered key indicators of DF and protein fermentation in the gut and are generally considered to have positive and negative impacts on gut health, respectively.…”

Partially defatted black soldier fly larva meal inclusion in piglet diets: effects on the growth performance, nutrient digestibility, blood profile, gut morphology and histological features

“…Morphometric analysis was performed by means of Image®-Pro Plus software, version 6.0 (Media Cybernetics Inc., Bethesda, Rockville, MD, USA). The evaluated morphometric indices were the villus height (Vh, from the top of the villus to the villus-crypt junction), crypt depth (Cd, from the villus-crypt junction to the base of the crypt) and the villus height to crypt depth ratio (Vh/Cd, calculated by dividing the villus height by the crypt depth) [39]. Morphometric measurements were performed on 10 well-oriented and intact villi and on 10 crypts chosen from the duodenum, jejunum and ileum [40].…”

Colonic Microbiota and Metabolites Response to Different Dietary Protein Sources in a Piglet Model

“…The weaning of piglets is often accompanied by low growth performance and a high risk of morbidity (mainly diarrhea rate) and death due to immature development of the gut and immune systems, which makes the piglets vulnerable to digestive disorders and highly susceptible to pathogenic bacteria (1–3). Indigestion causes excess undigested nutrients, mainly carbohydrates and protein, to flow into the hindgut where they are fermented by microbes.…”

“…The inclusion of high-quality of protein (milk by-products, animal proteins, processed proteins, etc.) (1, 2), the reduction of dietary protein intake or protein level (2, 3, 7), the addition of dietary fiber (8–10), and the use of various feed additives (1, 8) are commonly seen in swine production. These nutritional strategies can effectively reduce the outflow of undigested protein into the hindgut and decrease substrates for protein fermentation.…”