Ear wound healing in MRL/MpJ mice is associated with gut microbiome composition and is transferable to non-healer mice via microbiome transplantation

Objective

Adult elastic cartilage has limited repair capacity. MRL/MpJ (MRL) mice, by contrast, are capable of spontaneously healing ear punctures. This study was undertaken to characterize microbiome differences between healer and non-healer mice and to evaluate whether this healing phenotype can be transferred via gut microbiome transplantation.

Methods

We orally transplanted C57BL/6J (B6) mice with MRL/MpJ cecal contents at weaning and as adults (n = 57) and measured ear hole closure 4 weeks after a 2.0mm punch and compared to vehicle-transplanted MRL and B6 (n = 25) and B6-transplanted MRL (n = 20) mice. Sex effects, timing of transplant relative to earpunch, and transgenerational heritability were evaluated. In a subset (n = 58), cecal microbiomes were profiled by 16S sequencing and compared to ear hole closure. Microbial metagenomes were imputed using PICRUSt.

Results

Transplantation of B6 mice with MRL microbiota, either in weanlings or adults, improved ear hole closure. B6-vehicle mice healed ear hole punches poorly (0.25±0.03mm, mm ear hole healing 4 weeks after a 2mm ear hole punch [2.0mm—final ear hole size], mean±SEM), whereas MRL-vehicle mice healed well (1.4±0.1mm). MRL-transplanted B6 mice healed roughly three times as well as B6-vehicle mice, and half as well as MRL-vehicle mice (0.74±0.05mm, P = 6.9E-10 vs. B6-vehicle, P = 5.2E-12 vs. MRL-vehicle). Transplantation of MRL mice with B6 cecal material did not reduce MRL healing (B6-transplanted MRL 1.3±0.1 vs. MRL-vehicle 1.4±0.1, p = 0.36). Transplantation prior to ear punch was associated with the greatest ear hole closure. Offspring of transplanted mice healed significantly better than non-transplanted control mice (offspring:0.63±0.03mm, mean±SEM vs. B6-vehicle control:0.25±0.03mm, n = 39 offspring, P = 4.6E-11). Several microbiome clades were correlated with healing, including Firmicutes (R = 0.84, P = 8.0E-7), Lactobacillales (R = 0.65, P = 1.1E-3), and Verrucomicrobia (R = -0.80, P = 9.2E-6). Females of all groups tended to heal better than males (B6-vehicle P = 0.059, MRL-transplanted B6 P = 0.096, offspring of MRL-transplanted B6 P = 0.0038, B6-transplanted MRL P = 1.6E-6, MRL-vehicle P = 0.0031). Many clades characteristic of female mouse cecal microbiota vs. males were the same as clades characteristic of MRL and MRL-transplanted B6 mice vs. B6 controls, including including increases in Clostridia and reductions in Verrucomicrobia in female mice.

Conclusion

In this study, we found an association between the microbiome and tissue regeneration in MRL mice and demonstrate that this trait can be transferred to non-healer mice via microbiome transplantation. We identified several microbiome clades associated with healing.

Predicting the digestible energy of corn determined with growing swine from nutrient composition and cross-species measurements

The DE values of corn grain for pigs will differ among corn sources. More accurate prediction of DE may improve diet formulation and reduce diet cost. Corn grain sources ( = 83) were assayed with growing swine (20 kg) in DE experiments with total collection of feces, with 3-wk-old broiler chick in nitrogen-corrected apparent ME (AME) trials and with cecectomized adult roosters in nitrogen-corrected true ME (TME) studies. Additional AME data for the corn grain source set was generated based on an existing near-infrared transmittance prediction model (near-infrared transmittance-predicted AME [NIT-AME]). Corn source nutrient composition was determined by wet chemistry methods. These data were then used to 1) test the accuracy of predicting swine DE of individual corn sources based on available literature equations and nutrient composition and 2) develop models for predicting DE of sources from nutrient composition and the cross-species information gathered above (AME, NIT-AME, and TME). The overall measured DE, AME, NIT-AME, and TME values were 4,105 ± 11, 4,006 ± 10, 4,004 ± 10, and 4,086 ± 12 kcal/kg DM, respectively. Prediction models were developed using 80% of the corn grain sources; the remaining 20% was reserved for validation of the developed prediction equation. Literature equations based on nutrient composition proved imprecise for predicting corn DE; the root mean square error of prediction ranged from 105 to 331 kcal/kg, an equivalent of 2.6 to 8.8% error. Yet among the corn composition traits, 4-variable models developed in the current study provided adequate prediction of DE (model ranging from 0.76 to 0.79 and root mean square error [RMSE] of 50 kcal/kg). When prediction equations were tested using the validation set, these models had a 1 to 1.2% error of prediction. Simple linear equations from AME, NIT-AME, or TME provided an accurate prediction of DE for individual sources ( ranged from 0.65 to 0.73 and RMSE ranged from 50 to 61 kcal/kg). Percentage error of prediction based on the validation data set was greater (1.4%) for the TME model than for the NIT-AME or AME models (1 and 1.2%, respectively), indicating that swine DE values could be accurately predicted by using AME or NIT-AME. In conclusion, regression equations developed from broiler measurements or from analyzed nutrient composition proved adequate to reliably predict the DE of commercially available corn hybrids for growing pigs.

Comparison of broiler performance and carcass yields when fed diets containing genetically modified canola meal from event DP-Ø73496-4, near-isogenic canola meal, or commercial canola meals

Genetically modified (GM) canola (Brassica napus L.) line containing event DP-Ø73496-4 (hereafter referred to as 73496 canola) was produced by the insertion of the glyphosate acetyltransferase (gat4621) gene derived from Bacillus licheniformis. Expression of the GAT4621 protein present in 73496 canola plants confers in planta tolerance to the herbicidal active ingredient glyphosate. The objective of this study was to compare the nutritional performance of broiler chickens fed canola meal from 73496 canola seed with that of broiler chickens fed non-GM canola meal in a 42-d feeding trial. Diets were prepared using meal processed from seed from unsprayed 73496 plants or from plants sprayed with an in-field application of glyphosate herbicide [73496(S)]. For comparison, additional diets were produced with canola meal obtained from the non-GM near-isogenic control or non-GM commercial reference DuPont Pioneer brand varieties 42H72, 42H73, 46A65, and 44A89. Diets were fed to Ross 708 broilers (n = 120/group, 50% male and 50% female) in 3 phases: starter and grower phases containing 10 or 20% canola meal, respectively, and a finisher phase with a common corn-soybean meal diet without any canola meal. No statistically significant differences were observed in growth performance measures or organ and carcass yields between broilers consuming diets produced with canola meal from unsprayed or sprayed 73496 seed and those consuming diets produced with canola meal from control seed. Additionally, all performance, organ, and carcass measures from control, 73496, and 73496(S) canola treatment groups were within tolerance intervals constructed using data from the reference canola groups. It was concluded from these results that meal processed from 73496 canola seed (unsprayed plants or plants sprayed with glyphosate) was nutritionally equivalent to meal processed from non-GM near-isogenic control canola seed.

Comparison of broiler performance and carcass yields when fed transgenic maize grain containing event DP-O9814O-6 and processed fractions from transgenic soybeans containing event DP-356O43-5

The performance of broilers fed diets containing maize grain from event DP-Ø9814Ø-6 (98140; gat4621 and zm-hra genes) and processed fractions (meal, hulls, and oil) from soybeans containing event DP-356Ø43-5 (356043; gat4601 and gm-hra genes) was evaluated in a 42-d feeding study. Diets were produced with nontransgenic maize grain and soybean fractions from controls with comparable genetic backgrounds to 98140 and 356043 (control), 98140 maize and 356043 soybean (98140 + 356043), or 3 commercially available nontransgenic maize and soybean combinations. Ross 708 broilers (n = 120/group; 50% male, 50% female) were fed diets in 3 phases: starter (d 0 to 21), grower (d 22 to 35), and finisher (d 36 to 42). Starter diets contained (on average) 63% maize and 28% soybean meal, grower diets 66% maize and 26% soybean meal, and finisher diets 72% maize and 21% soybean meal; soybean hulls and oils were held constant at 1.0 and 0.5%, respectively, across all diets in all phases. Weight gain, feed intake, and mortality-adjusted feed efficiency were calculated for d 0 to 42. Standard organ and carcass yield data were collected on d 42. Data were analyzed using a mixed model ANOVA with differences between control and 98140 + 356043 group means considered significant at P < 0.05. Reference group data were used only to estimate experimental variability and to generate tolerance intervals. No significant differences were observed in weight gain, mortality, mortality-adjusted feed efficiency, organ yields, or carcass yields between broilers consuming diets produced with 98140 + 356043 and those consuming diets produced with control maize and soybean fractions. All values of response variables evaluated in the control and 98140 + 356043 groups fell within calculated tolerance intervals. Based on these results, it was concluded that the combination of genetically modified 98140 maize and 356043 soybean fractions was nutritionally equivalent to nontransgenic maize and soybean controls with comparable genetic backgrounds.

Nutritional equivalency evaluation of transgenic maize grain from event DP-O9814O-6 and transgenic soybeans containing event DP-356O43-5: laying hen performance and egg quality measures

The objective of this study was to compare the nutritional performance of laying hens fed maize grain from event DP-Ø9814Ø-6 (98140; gat4621 and zm-hra genes) and processed soybean meal from soybeans containing event DP-356Ø43-5 (356043; gat4601 and gm-hra genes), individually or in combination, with the performance of hens fed diets containing nontransgenic maize and soybean meal. Healthy pullets (n = 216) placed in cages (3 hens/cage) were randomly assigned to 9 dietary treatments (8 cages/treatment): nontransgenic controls 1, 2, and 3 (comparable genetic background controls for 98140, 356043, and 98140 + 356043, respectively); reference 1, reference 2, and reference 3 (commercially available nontransgenic maize-soybean meal sources); and 98140 (test 1), 356043 (test 2), and 98140 + 356043 (test 3). The experiment was divided into three 4-wk phases (24 to 28 wk, 28 to 32 wk, and 32 to 36 wk of age), during which time hens were fed mash diets. Performance (BW, feed intake, and egg production) and egg quality data were collected. Data were analyzed using a mixed model ANOVA; differences between the control and respective test group means were considered significant at P < 0.05. Data generated from the reference groups were used only in the estimation of experimental variability and in generating the tolerance interval. Body weight and BW gain, egg production, and production efficiency for hens fed the test diets were similar to the respective values for hens fed the corresponding control diets. Haugh unit measures and egg component weights were similar between the respective test and control groups, and no differences were observed in quality grades or crack measures. All observed values of the control and test groups were within the calculated tolerance intervals. This research indicates that the performance and egg quality of hens fed diets containing 98140 maize grain, 356043 soybean meal, or a combination of the 2 was comparable with that of hens fed diets formulated with nontransgenic maize grain or soybean meal control diets with comparable genetic backgrounds.

Comparison of broiler performance and carcass yields when fed diets containing transgenic maize grains from event DP-O9814O-6 (Optimum GAT), near-isogenic control maize grain, or commercial reference maize grains

A genetically modified maize (Zea mays L.) line that contains the Optimum GAT trait (event DP-Ø9814Ø-6; 98140) was produced by integration of the gat4621 and zm-hra genes. The expressed GAT4621 and ZM-HRA proteins confer tolerance to the herbicidal active ingredient glyphosate and acetolactate synthase-inhibiting herbicides, respectively. The objective of this study was to compare the nutritional performance of 98140 maize grain to nontransgenic maize grain in a 42-d feeding trial in broiler chickens. Diets were prepared using grain from untreated 98140 plants and from plants treated with an in-field application of herbicides (98140 + Spray). For comparison, additional diets were produced with maize grain obtained from the nontransgenic near-isogenic control (control) and nontransgenic commercial reference Pioneer brand hybrids 33J56, 33P66, and 33R77. Diets were fed to Ross x Cobb broilers (n = 120/group, 50% male and 50% female) in 3 phases: starter, grower, and finisher containing 58.5, 64, and 71.5% maize grain, respectively. No statistically significant differences were observed in mortality, growth performance variables, or carcass and organ yields between broilers consuming diets produced with maize grains from unsprayed or sprayed 98140 and those consuming diets produced with near-isogenic control maize grain. Additionally, all performance and carcass variables from control, 98140, and 98140 + Spray test maize treatment groups were within tolerance intervals constructed using data from reference maize groups. Based on these results, it was concluded that 98140 maize grain (unsprayed or sprayed with a herbicide mixture) was nutritionally equivalent to nontransgenic control maize with comparable genetic background.

Comparison of broiler performance when fed diets containing event DP-3O5423-1, nontransgenic near-isoline control, or commercial reference soybean meal, hulls, and oil

DP-3Ø5423-1 (305423) is a genetically modified soybean that was produced by biolistic insertion of the gm-fad2-1 gene fragment and gm-hra genes into the germline of soybean seeds. Expression of gm-fad2-1 results in greater concentrations of oleic acid (18:1) by suppressing expression of the endogenous FAD2-1 gene, which encodes an n-6 fatty acid desaturase enzyme that catalyzes desaturation of 18:1 to linoleic acid (18:2). The GM-HRA protein expressed by the gm-hra gene is a modified version of the soybean acetolactate synthase enzyme that is used as a selectable marker during transformation. A 42-d feeding trial was conducted with broiler chickens to compare the nutritional performance of 305423 soybeans with nontransgenic soybeans. Diets were prepared using processed fractions (meal, hulls, and oil) from 305423 soybean plants. For comparison, additional diets were produced with soybean fractions obtained from a nontransgenic near-isoline (control) and nontransgenic commercial Pioneer brand varieties (93B86, 93B15, and 93M40). Diets were fed to Ross x Cobb broilers (n = 120/group, 50% male and 50% female) in 3 phases. Starter, grower, and finisher diets contained 26.5, 23, and 21.5% soybean meal, respectively. Soybean hulls and oil were added at 1.0 and 0.5%, respectively, across all diets in each phase. No statistically significant differences were observed in growth performance (BW, mortality, feed efficiency), organ yield (liver and kidney), or carcass yield (breast, thigh, leg, wing, and abdominal fat) variables between broilers consuming diets prepared with isolated fractions from 305423 or near-isoline control soybean. Additionally, all performance and carcass variables from control and 305423 soybean treatment groups fell within tolerance intervals constructed for each response variable using data from broilers fed diets prepared with reference soybean fractions. Based on the results from this study, it was concluded that 305423 soybeans were nutritionally equivalent to non-transgenic control soybeans with a comparable genetic background.

Comparison of broiler performance when fed diets containing event DP-356Ø43-5 (Optimum GAT), nontransgenic near-isoline control, or commercial reference soybean meal, hulls, and oil

Event DP-356Ø43-5 (356043; Optimum GAT) is a genetically modified soybean (Glycine max) that was produced by insertion of the gat4601 and gm-hra genes. The expression products of these genes are the glyphosate acetyltransferase 4601 and acetolactate synthase proteins, respectively. Expression of the glyphosate acetyltransferase 4601 protein confers tolerance in planta to the herbicidal active ingredient glyphosate, whereas expression of the acetolactate synthase protein confers tolerance to sulfonylurea and imidazolinone herbicides. The objective of this study was to compare the nutritional equivalence of 356043 soybeans to nontransgenic soybeans in a 42-d feeding trial in broiler chickens. Diets were prepared using processed fractions (meal, hulls, and oil) from untreated 356043 soybean plants or from soybean plants treated with a mixture of glyphosate, chlorimuron, and thifensulfuron (356043 + Gly/SU). For comparison, additional diets were produced with soybean fractions obtained from a nontransgenic near-isoline (control; 091) and nontransgenic commercial Pioneer varieties (93B86, 93B15, and 93M40). Diets were fed to Ross x Cobb broilers (n = 120/group, 50% male and 50% female) in 3 phases. Starter diets contained 30% soybean meal, grower diets 26% soybean meal, and finisher diets 21.5% soybean meal. Soybean hulls and oil were added at 1.0 and 0.5%, respectively, across all diets in each phase. No statistically significant differences were observed in mortality, growth performance variables, or carcass and organ yields between broilers consuming diets produced with 356043 or 356043 + Gly/SU soybean fractions and those consuming diets produced with near-isoline control soybean fractions. Additionally, all performance and carcass variables from control, 356043, and 356043 + Gly/SU soybean treatment groups fell within the tolerance intervals constructed using data from reference soybean groups. Based on the results from this study, it was concluded that 356043 soybean was nutritionally equivalent to nontransgenic control soybean with a comparable genetic background.

Influence of Graphite Addition on the Reactivity of Ti Powder with H2 under Ball Milling

The effect of graphite addition on the mechanism of hydrogen uptake by titanium during mechanochemical activation in hydrogen flow was studied using kinetic, structural, microscopic, and spectroscopic techniques. As was found, already a small graphite admixture of about 0.5 wt % changed the kinetics of mechanically induced H2 sorption and significantly stimulated Ti-H2 interaction. Two new types of occupation sites available for hydrogen were observed, which are characterized by low H2 desorption temperatures: about 650 and 750 K instead of 1000 K.

Effects of oral versus intravenous nutrition on intestinal adaptation after small bowel resection in the dog

To study the influence of luminal nutrition on the structural and functional adaptive changes which are seen in the residual intestine after partial small bowel resection, quantitative histology, in vitro uptake of 14C l-leucine, mucosal enzyme activities, and in vivo absorption of glucose were studied before and 6 weeks after 50% proximal small bowel resection in 10 greyhound dogs, 5 of which were nourished exclusively by the intravenous route while 5 were pair-fed by mouth. In the orally fed jejunectomized dogs, the ileum became dialed with mucosal hyperplasia, the villus height increased from 796 +/- SEM 26 mum to 1102 +/- 28 mum (P less than 0.001), and there was a corresponding increase in glucose absorption in vivo (milligrams -centimeter of intestine -1min-1) from 5.3 +/- 1.2 to 10.1 +/-1.6. The increased absorption seems mainly caused by the dilation and villus hyperplasia, since there was no significant change in in vitro absorption and mucosal enzyme activity when expressed per unit weight of intestine. In the absence of exogenous luminal nutrition, the well nourished intravenously fed dogs showed no evidence of functional adaptation and a significant fall in mean ileal villus height from 823 +/-48 mum at the initial operation to 732 +/-57 mum 6 weeks after jejunectomy. These results provide the most direct evidence to date that luminal nutrition is essential for the development of intestinal adaptation after resection. They also suggest that luminal contents are necessary to maintain the structural and functional integrity of the normal small bowel.