Novel secreted maltase activity enables suckling mouse pup starch digestion

The ruminal fungi Orpinomyces joyonii strain 19-2, Neocallimastix patriciarum strain 27, and Piromyces communis strain 22 were examined for their ability to digest cereal starch. All strains digested corn starch more readily than barley or wheat starch. Orpinomyces joyonii 19-2 exhibited the greatest propensity to digest starch in wheat and barley, whereas the digestion of these starches by N. patriciarum 27 and P. communis 22 was limited. Media ammonia concentrations were lower when fungal growth was evident, suggesting that all strains assimilate ammonia. Fungi formed extensive rhizoidal systems on the endosperm of corn, but O. joyonii 19-2 was the only strain to form such systems on the endosperm of wheat and barley. All strains penetrated the protein matrix of corn but did not penetrate starch granules. Starch granules from all three cereals were pitted, evidence of extensive digestion by extracellular amylases produced by O. joyonii 19-2. Similar pitting was observed on the surface of corn starch granules digested by N. patriciarum 27 and P. communis 22, but not on wheat and barley starch granules. The ability of ruminal fungi to digest cereal grains depends on both the strain of fungus and the type of grain. The extent to which fungi digest cereal grain in the rumen remains to be determined.Key words: ruminal fungi, cereal grain, starch digestion, ruminant.

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Natural ‘capsule’ in food plants: Cell wall porosity controls starch digestion and fermentation

Food Hydrocolloids ◽

10.1016/j.foodhyd.2021.106657 ◽

2021 ◽

Vol 117 ◽

pp. 106657

Author(s):

Hai-Teng Li ◽

Si-Qian Chen ◽

Alexander T. Bui ◽

Bin Xu ◽

Sushil Dhital

Keyword(s):

Cell Wall ◽

Food Plants ◽

Starch Digestion ◽

Cell Wall Porosity

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La Crosse Virus Shows Strain-Specific Differences in Pathogenesis

Pathogens ◽

10.3390/pathogens10040400 ◽

2021 ◽

Vol 10 (4) ◽

pp. 400

Author(s):

Sarah N. Wilson ◽

Krisangel López ◽

Sheryl Coutermash-Ott ◽

Dawn I. Auguste ◽

Danielle L. Porier ◽

...

Keyword(s):

Public Health ◽

North America ◽

Viral Encephalitis ◽

Strain Selection ◽

La Crosse Virus ◽

Murine Models ◽

Suckling Mouse ◽

Important Public Health ◽

Representative Strain ◽

Ancestral Strain

La Crosse virus (LACV) is the leading cause of pediatric viral encephalitis in North America, and is an important public health pathogen. Historically, studies involving LACV pathogenesis have focused on lineage I strains, but no former work has explored the pathogenesis between or within lineages. Given the absence of LACV disease in endemic regions where a robust entomological risk exists, we hypothesize that some LACV strains are attenuated and demonstrate reduced neuroinvasiveness. Herein, we compared four viral strains representing all three lineages to determine differences in neurovirulence or neuroinvasiveness using three murine models. A representative strain from lineage I was shown to be the most lethal, causing >50% mortality in each of the three mouse studies. However, other strains only presented excessive mortality (>50%) within the suckling mouse neurovirulence model. Neurovirulence was comparable among strains, but viruses differed in their neuroinvasive capacities. Our studies also showed that viruses within lineage III vary in pathogenesis with contemporaneous strains, showing reduced neuroinvasiveness compared to an ancestral strain from the same U.S. state (i.e., Connecticut). These findings demonstrate that LACV strains differ markedly in pathogenesis, and that strain selection is important for assessing vaccine and therapeutic efficacies.

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Application of a dynamic mechanistic model of small intestinal starch digestion in the dairy cow

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200007602 ◽

2002 ◽

Vol 2002 ◽

pp. 104-104

Author(s):

J. A. N. Mills ◽

E. Kebreab ◽

L. A. Crompton ◽

J. Dijkstra ◽

J. France

Keyword(s):

Experimental Data ◽

Small Intestine ◽

Dairy Cow ◽

Energy Recovery ◽

Mechanistic Model ◽

Biological Knowledge ◽

Dietary Energy ◽

Starch Digestion ◽

High Contribution ◽

Small Intestinal

The high contribution of postruminal starch digestion (>50%) to total tract starch digestion on certain energy dense diets (Mills et al. 1999) demands that limitations to small intestinal starch digestion are identified. Therefore, a dynamic mechanistic model of the small intestine was constructed and evaluated against published experimental data for abomasal carbohydrate infusions in the dairy cow. The mechanistic structure of the model allowed the current biological knowledge to be integrated into a system capable of identifying restrictions to dietary energy recovery from postruminal starch delivery.

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261 Increasing dietary amylose reduces rate of starch digestion and increases microbial fermentation in weaned pigs

Journal of Animal Science ◽

10.1093/jas/skaa054.152 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 86-86

Author(s):

F P Y Tan ◽

L F Wang ◽

E Beltranena ◽

R T Zijlstra

Keyword(s):

Growth Rate ◽

Block Design ◽

Optimal Growth ◽

Metabolite Profile ◽

Proximal Colon ◽

Starch Digestion ◽

Gut Health ◽

Weaned Pigs ◽

Ileal Digestibility ◽

Beneficial Effects

Abstract Beneficial effects of SCFA in modulating gut health stimulated interest on dietary strategies to increase intestinal microbial activity and digesta SCFA. Amylose has lower apparent ileal digestibility (AID) than amylopectin. In the large intestine, undigested starch is fermented by microbes producing SCFA. The objective was to determine effects of increasing dietary amylose on starch flow and metabolite profile along the intestinal tract in weaned pigs. Weaned pigs (n=32; initial BW, 8.4 kg) were randomly allocated to 4 diets containing 67% starch with 0, 20, 35, or 70% amylose in a randomized complete block design. On day 21, pigs were euthanized to collect digesta and feces for evaluating starch digestion and metabolite profiles. Apparent hindgut fermentation (AHF) was calculated as apparent total tract digestibility minus AID. Feed intake was 12% lower (P < 0.05) and growth rate was 18% lower (P < 0.05) for pigs fed 70% amylose than pigs fed 0, 20, or 35% amylose. Feed efficiency was greatest (P < 0.05) for pigs fed with 35% amylose. The AID of starch was 44% lower (P < 0.05) in pigs fed 70% amylose. Starch was completely digested by the proximal colon in pigs fed 0, 20, or 35% amylose, but AHF of starch was 14% greater (P < 0.05) in pigs fed 70% amylose. Increasing dietary amylose did not alter digesta SCFA in the small intestine, but increased (P < 0.05) digesta SCFA in the cecum, specifically acetate and total SCFA, and increased (P < 0.05) propionate and valerate in all sections of the colon. In conclusion, increasing dietary amylose in weaned pigs stimulated hindgut fermentation of starch with a corresponding increase in digesta total SCFA in the cecum and colon. Optimizing dietary amylose may exert its effect as dietary prebiotic while promoting an optimal growth rate in young pigs.

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