Corn hybrid affects in vitro and in vivo measures of nutrient digestibility in dogs

Abstract

Corn is a commonly used ingredient in dry pet foods because there is a stable supply and it is a relatively inexpensive source of nutrients. Corn hybrids are available that are higher in CP and amylose and lower in phytate concentration than conventional hybrids. Approximately 500 mg of high-protein (HP), high-protein, low-phytate (HPLP), and high-amylose (HA) corn were compared with conventional (CONV) corn and amylomaize starch (AM) in triplicate and exposed to pepsin/hydrochloric acid and pancreatin to simulate hydrolytic digestion. Substrate remaining after this was used to determine in vitro colonic fermentation. Organic matter disappearances as a result of hydrolytic digestion were >80% for CONV, HP, and HPLP, whereas HA (60.7%) and AM (43.7%) were lower (P < 0.05). Total digestion (TD) values after hydrolytic digestion and 8 h of fermentation using canine fecal inoculum were greater (P < 0.05) for CONV, HP, and HPLP vs. HA and AM. The residue left after hydrolytic digestion of all substrates was poorly fermented. Five ileal-cannulated dogs were fed each corn hybrid at approximately 31% of the diet in a 5 x5 Latin square design. Dogs fed diets containing HP corn had higher (P < 0.05) ileal OM digestibility (70.3%) and tended (P < 0.10) to have higher DM digestibility (64.6%). Ileal starch digestibilities were lower (P < 0.05) for dogs fed HA (64.0%) and AM (63.0%). Ileal digestibilities of essential (71.2%), nonessential (67.4%), and total (69.0%) AA tended to be higher (P < 0.10) for HP diets compared with CONV (66.4, 62.4, and 64.0%, respectively). Total-tract DM, OM, CP, and GE digestibilities (77, 82, 77, and 84%, on average, respectively) were higher (P < 0.05) for dogs fed CONV, HP, and HPLP than for those fed AM (66.9, 71.6, 72.6, and 76.5%) and HA (60.6, 65.7, 69.7, and 71.5%). Total-tract fat digestibilities were lower (P < 0.05) for dogs fed HA diets (86.6%) than for all other treatments (91.0%, on average). Total-tract starch digestibilities were higher (P < 0.05) for dogs fed CONV, HP, and HPLP (98%, on average) compared with HA (72.8%) and AM (76.5%). No differences were detected among treatments in fecal bifidobacteria, lactobacilli, or Clostridium perfringens concentrations. The experiments demonstrated that HP and HPLP corn had hydrolytic digestion and fermentation characteristics similar to those of CONV corn, whereas HA resulted in similar responses to AM, a well-established resistant starch ingredient.

High-Throughput Sequence-Based Analysis of the Intestinal Microbiota of Weanling Pigs Fed Genetically Modified MON810 Maize Expressing Bacillus thuringiensis Cry1Ab (Bt Maize) for 31 Days

“…Minor differences in maize composition were also found in previous studies comparing GM and non-GM maize (2,51). Although nutrient differences between the Bt maize and isogenic maize may be a result of the cry1Ab gene insertion, natural variation in nutrient composition is frequently observed between non-GM maize varieties (12,16,17,21,24,36,58). Furthermore, it has been concluded in a study by Barros et al (3) that environmental factors can affect maize composition more than the genetic modification itself.…”

Protein and amino acid bioavailability estimates for canine foods

“…Bednar et al (2000) used various ingredients that contained protein including wheat, corn, wheat gluten meal, beef and bone meal, poultry byproduct meal, or poultry meal. Diets used by Clapper et al (2001) contained chicken bone residue next to a protein source and Gajda et al (2005) used various protein sources. Although 5 other studies were found to report apparent ileal CP and AA digestibility values in adult dogs, their data were not used in the present study.…”

“…A previously reported data set (Hendriks et al, 2012) was supplemented with data from 5 studies (Zentek, 1995;Johnson et al, 1998;Gajda et al, 2005;Hendriks et al, 2013;Tjernsbekk et al, 2014) to contain data on 158 canine diets used in fundamental nutritional research, formulated to evaluate specific ingredients or investigate specific technological treatments. The data set contained information on BW, food intake, dietary N content, and apparent fecal and apparent ileal digestibility of N. From 24 diets reported in 6 studies (Bednar et al, 2000;Clapper et al, 2001;Gajda et al, 2005;Tjernsbekk et al, 2014), apparent ileal digestibility values of individual AA were also collected.…”

“…The data set contained information on BW, food intake, dietary N content, and apparent fecal and apparent ileal digestibility of N. From 24 diets reported in 6 studies (Bednar et al, 2000;Clapper et al, 2001;Gajda et al, 2005;Tjernsbekk et al, 2014), apparent ileal digestibility values of individual AA were also collected. Studies where diets were used composed of only 1 protein source (e.g., soybean meal, meat meal) were excluded as these were considered to be not representative for commercial diet compositions.…”

Barley as an alternative to rice in dog food

“…Well-digested products cause stiff and shaped stools. The fecal consistency may vary on a scale of 1 to 5 from watery to solid (5,(17)(18)(19)(20) or some studies rate watery as 1 whereas others rate it as 5 (14,21).…”