Effect of dietary mineral level and inulin inclusion on phosphorus, calcium and nitrogen utilisation, intestinal microflora and bone development.
BACKGROUND
An experiment was conducted to investigate the interaction between dietary phosphorus (P) level (4 vs 6 g total P kg(-1)) and inulin inclusion (0 vs 20 g kg(-1)) on coefficients of total tract apparent digestibility, nitrogen (N), P and calcium (Ca) utilisation, bone mineralisation, selected gastrointestinal microflora, intestinal volatile fatty acid concentrations and digesta pH in the ileum, caecum and proximal colon. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary Ca level in order to maintain a sustainable dietary Ca/P ratio. Entire male finisher pigs (n = 10 per treatment) with a similar initial body weight (51 kg, standard deviation 2.4 kg) were used.


RESULTS
Inulin inclusion lowered (P < 0.01) Enterobacteriaceae populations in the proximal colon compared with pigs offered diets without added inulin. However, intestinal bacterial populations of Lactobacillus and Bifidobacterium spp. were unaffected. Inulin inclusion had no effect on mineral digestibility or bone mineralisation. Pigs offered low P and Ca diets had lower (P < 0.01) bone mineralisation than pigs offered high P and Ca diets.


CONCLUSIONS
Intestinal bacterial populations of Enterobacteriaceae in the proximal colon were lowered by inulin inclusion. Inulin inclusion did not affect P, Ca or N utilisation or bone mineralisation in the finisher pig when offered either a low or a high P diet. Increasing the P and Ca content of the diet led to an increase in bone mineralisation.
Varley
Patrick F
PF
University College Dublin, School of Agriculture, Food Science and Veterinary Medicine, Lyons Research Farm Newcastle, Co. Dublin, Ireland.
McCarney
Catherine
C
Callan
James J
JJ
O'Doherty
John V
JV
D000821:Animal Feed; D000818:Animals; D001419:Bacteria / Q000187:drug effects*; D001644:Bifidobacterium / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects*; D002136:Calcium, Dietary / Q000378:metabolism* / Q000494:pharmacology; D003106:Colon / Q000187:drug effects* / Q000382:microbiology; D004755:Enterobacteriaceae / Q000187:drug effects; D007444:Inulin / Q000494:pharmacology*; D007778:Lactobacillus / Q000187:drug effects; D008297:Male; D008903:Minerals / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology; D016226:Phosphorus, Dietary / Q000378:metabolism* / Q000494:pharmacology; D056692:Prebiotics; D013025:Glycine max; D013552:Swine; D014131:Trace Elements / Q000378:metabolism*; D014908:Triticum
D002136:Calcium, Dietary; D008903:Minerals; D016226:Phosphorus, Dietary; D056692:Prebiotics; D014131:Trace Elements; D007444:Inulin; D009584:Nitrogen