True phosphorus digestibility and the endogenous phosphorus outputs associated with brown rice for weanling pigs measured by the simple linear regression analysis technique

Abstract

The objectives of this study were to determine true phosphorus (P) digestibility, degradability of phytate-P complex and the endogenous P outputs associated with brown rice feeding in weanling pigs by using the simple linear regression analysis technique. Six barrows with an average initial body weight of 12.5 kg were fitted with a T-cannula and fed six diets according to a 6 £ 6 Latin-square design. Six maize starch-based diets, containing six levels of P at 0.80, 1.36, 1.93, 2.49, 3.04, and 3.61 g/kg per kg dry-matter (DM) intake (DMI), were formulated with brown rice. Each experimental period lasted 10 days. After a 7-day adaptation, all faecal samples were collected on days 8 and 9. Ileal digesta samples were collected for a total of 24 h on day 10. The apparent ileal and faecal P digestibility values of brown rice were affected ( P , 0.01) by the P contents in the assay diets. The apparent ileal and faecal P digestibility values increased from 248.0 to 36.7% and from 235.6 to 40.0%, respectively, as P content increased from 0.80 to 3.61 g/kg DMI. Linear relationships ( P , 0.05), expressed as g/kg DMI, between the apparent ileal and faecal digestible P and dietary levels of P, suggested that true P digestibility and the endogenous P outputs associated with brown rice feeding could be determined by using the simple regression analysis technique. There were no differences ( P . 0.05) in true P digestibility values (57.7^5.4 v. 58.2^5.9%), phytate P degradability (76.4^6.7 v. 79.0^4.4%) and the endogenous P outputs (0.812^0..096 v. 0.725^0.083 g/kg DMI) between the ileal and the faecal levels. The endogenous faecal P output represented 14 and 25% of the National Research Council (1998) recommended daily total and available P requirements in the weanling pig, respectively. About 58% of the total P in brown rice could be digested and absorbed by the weanling pig. Our results suggest that the large intestine of the weanling pigs does not play a significant role in the digestion of P in brown rice. Diet formulation on the basis of total or apparent P digestibility with brown rice may lead to P overfeeding and excessive P excretion in pigs.

Effect of phytase on true total tract digestibility of phosphorus in full-fat rice bran determined in pigs by regression method

“…Similar results can be seen in studies that evaluated the P digestibility in corn (13) and brown rice (18).…”

Nutrient digestibility response to graded dietary levels of sodium chloride in weanling pigs

“…The apparent faecal digestibility values for DM, CP, Ca and P in the experimental diets were calculated according to the equation where D A i is the apparent faecal DM, CP, Ca or P digestibility value in the i th assay diet (% as‐fed basis), ID is the digestibility marker concentration in the assay diet (% as‐fed basis), PI is the DM, CP, Ca or P concentration in the faeces (% as‐fed basis), II is the digestibility marker concentration in the faeces (% as‐fed basis) and PD is the DM, CP, Ca or P concentration in the assay diet (% as‐fed basis) 15, 16…”

Endogenous losses and true digestibility of phosphorus in rice bran with or without phytase determined with piglets

“…The negative values of RB digestible P (PDIG RB ) that were observed when adding 5% RB occurred because the amount of P in feces was larger than the ingested content (YANG et al, 2007).…”