Urinary excretion of advanced glycation end products in dogs and cats.

The present study was conducted with privately owned dogs and cats to investigate whether a relationship exists between the dietary AGEs and the urinary excretion of AGEs, as indication of possible effective absorption of those compounds in the intestinal tract of pet carnivores. For this purpose, data were collected from both raw fed and dry processed food (DPF) fed to dogs and cats, through spot urine sampling and questionnaires. Raw pet food (RF, low in AGE diets) was fed as a primary food source to 29 dogs and DPF to 28 dogs. Cats were categorized into 3 groups, which were RF (n = 15), DPF (n = 14) and dry and wet processed pet food (DWF, n = 25). Urinary-free carboxymethyllysine (CML), carboxyethyllysine (CEL) and lysinoalanine (LAL) were analysed using ultrahigh-performance liquid chromatography (UHPLC)-mass spectrometry, and were standardized for variable urine concentration by expressing the AGE concentrations as a ratio to urine creatinine (Ucr) concentration (µg/µmol Ucr). Urinary excretion of CML, CEL and LAL in dogs fed with DPF was 2.03, 2.14 and 3 times higher compared to dogs fed with RF (p < .005). Similar to the dogs, a significant difference in CML:Ucr, CEL:Ucr and LAL:Ucr between the three diet groups was observed in cats (p-overall < 0.005, ANOVA), in which the RF fed group excreted less AGEs than the other groups. Linear regression coefficients and SE of CML:Ucr, CEL:Ucr and LAL:Ucr showed that body weight and neuter status were significantly correlated with CML and CEL excretion, but not to LAL excretion. Our results revealed a significant correlation between dietary AGEs and urinary excretion of free CML, CEL and LAL, and also showed that endogenous formation of these AGEs occurs in both dogs and cats under physiological conditions.

Isolipidic replacement of krabok oil by whole krabok seed reduces in vitro methanogenesis, but negatively affects fermentation.

The background of the current in vitro study involves the issue of methane (CH4 ) production inherent to rumen fermentation. One of the dietary strategies to reduce enteric CH4 production by ruminants involves the supplementation of medium-chain fatty acids in diets. As such, oils containing high amounts of MCFA, such as coconut, palm kernel and krabok oil, are of much interest to formulate energy efficient and environmentally friendly rations for ruminants. Krabok oil (KO) reduces methanogenesis, but the appropriate inclusion level of dietary KO is unclear. We therefore investigated the dose-response relationship between krabok oil and CH4 production. In practice, the use of whole krabok seed (WKS), instead of KO, is easier, but the efficacy of WKS to inhibit methanogenesis was hitherto unknown. Thus, we also investigated whether WKS provides an alternative tool to inhibit CH4 production. The experimental substrates contained either KO, WKS, the residue of WKS after fat extraction residue (FER) or FER + KO. Appropriate amounts of WKS or its derivatives were added to a basal substrate so as to attain either a low, medium or high content of KO, that is, 37-46, 90-94 and 146-153 g/kg dry matter respectively. The experimental substrates were formulated to keep the amounts of incubated fat-free OM, crude protein, neutral detergent fibre and acid detergent fibre constant in order to avoid biased results through potential differences in fermentability between WKS and its derivatives, and the basal substrate. The latter resembled the ingredient composition of a total mixed ration commonly used in Thai dairy cows. Fully automated gas production (GP) equipment was used to measure gas- and CH4 production. Irrespective of the type of substrate (p ≥ .115), both the absolute (ml/g fat-free OM) and relative (% of total GP) CH4 production was reduced at the highest inclusion level of WKS or its derivatives (p ≤ .019). Total GP (ml/g fat-free OM), however, was reduced after incubation of FER, FER + KO, and WKS, but not KO, at the highest inclusion level of the respective substrates (p = .019). Volatile fatty acids were likewise affected (p ≤ .001). Krabok oil can inhibit CH4 production but only when the dietary KO content is at least 9.4% (DM). Supplementation of KO in the form of WKS, however, is considered not opportune because the fat extracted residue of WKS is poorly degraded during fermentation.

Response of saliva Na/K ratio to changing Na supply of lactating cows under tropical conditions.

BACKGROUND: Factorial determination of the sodium (Na) requirement of heat-stressed lactating cows is hindered by accurate estimates of the Na losses through sweat. Direct studies, therefore, may be needed requiring information on the time course of healthy animals to become Na depleted and the subsequent rate of repletion. The rate of Na depletion and subsequent rate of Na repletion with two levels of dietary Na to lactating dairy cows housed under tropical conditions were investigated using the salivary Na/K. RESULTS: The 12 lactating cows (salivary Na/K ratio 14.6) rapidly developed clinical signs of Na deficiency, including pica, polyuria and polydipsia, reduced body weight and reduced milk yield when fed a low-Na ration (0.33 g kg-1 dry matter (DM)) for 3 weeks. Deficiency symptoms were associated with a rapid decrease in salivary Na/K ratio to <4.3 from 7 to 21 days. Subsequent repletion of the cows with NaCl to a ration concentration of 1.1 or 1.6 g Na kg-1 DM for 5 weeks did not restore salivary Na/K ratio to values of >6. CONCLUSION: A daily Na intake of heat-stressed lactating cows to a ration intake of 1.6 g Na kg-1 DM was insufficient to restore Na deficiency. One week was sufficient to deplete heat-stressed lactating cows of Na, allowing for rapid dose-response studies utilizing the salivary Na/K ratio as a parameter for Na status of cows under tropical conditions. © 2016 Society of Chemical Industry.

Exposure to a novel feedstuff by goat dams during pregnancy and lactation versus pregnancy alone does not further improve post-weaning acceptance of this feedstuff by their kids.

BACKGROUND: Previous experiments demonstrated the existence of in utero learning in goats. However, in contrast to other animal species, in goats there is no information about the potential of flavour transmission from maternal feed to goat kids during lactation. The aim of the current study was to assess the role of post-natal exposure of Chromonaela odorata leaf meal (COLM) in relation to the preferences to this feedstuff by goat kids after weaning. It was hypothesised that exposure of COLM to the dams during both pregnancy and lactation versus pregnancy alone, additionally affects post-weaning intake of COLM by their offspring. RESULTS: Consumption of COLM by the goat kids was similar during the first week post-weaning for all treatments. However, after 4 weeks the intake of COLM was at least 1.8 times greater when kids were exposed to COLM during pregnancy whereas it remained virtually unchanged when kids were exposed to COLM during lactation only. The increase in COLM consumption was in line with the observations on latency to eat and meal size. CONCLUSION: Transmission of feeding behaviour from goat dams to offspring does not occur during lactation. However, the concept of in utero learning in goats was confirmed.

The effects of additives in napier grass silages on chemical composition, feed intake, nutrient digestibility and rumen fermentation.

The effect of silage additives on ensiling characteristics and nutritive value of Napier grass (Pennisetum purpureum) silages was studied. Napier grass silages were made with no additive, fermented juice of epiphytic lactic acid bacteria (FJLB), molasses or cassava meal. The ensiling characteristics were determined by ensiling Napier grass silages in airtight plastic pouches for 2, 4, 7, 14, 21 and 45 d. The effect of Napier grass silages treated with these additives on voluntary feed intake, digestibility, rumen fermentation and microbial rumen fermentation was determined in 4 fistulated cows using 4×4 Latin square design. The pH value of the treated silages rapidly decreased, and reached to the lowest value within 7 d of the start of fermentation, as compared to the control. Lactic acid content of silages treated with FJLB was stable at 14 d of fermentation and constant until 45 d of ensiling. At 45 d of ensiling, neutral detergent fiber (NDF) and acid detergent fiber (ADF) of silage treated with cassava meal were significantly lower (p<0.05) than the others. In the feeding trial, the intake of silage increased (p<0.05) in the cow fed with the treated silage. Among the treatments, dry matter intake was the lowest in the silage treated with cassava meal. The organic matter, crude protein and NDF digestibility of the silage treated with molasses was higher than the silage without additive and the silage treated with FJLB. The rumen parameters: ruminal pH, ammonia-nitrogen (NH3-N), volatile fatty acid (VFA), blood urea nitrogen (BUN) and bacterial populations were not significantly different among the treatments. In conclusion, these studies confirmed that the applying of molasses improved fermentative quality, feed intake and digestibility of Napier grass.

High intake of magnesium in relation to the ruminal transmural potential difference and magnesium absorption in wethers.

High potassium (K) intakes are known to decrease magnesium (Mg) absorption in ruminants by increasing the transmural potential difference (PDt, serosal side = positive). High Mg intakes are known to increase the amount of Mg absorbed, which may be explained by increasing the ruminal Mg concentration, but an effect on the PDt cannot be excluded. The objective of this study was to determine whether or not Mg intake affects the PDt. In a 3 x 3 Latin square design, six ruminally fistulated wethers were fed a low-Mg, low-K ration (3.88 g Mg/kg dry matter (DM); 30.7 g K/kg DM), a high-Mg, low K-ration (16.79 g Mg/kg DM; 30.7 g K/kg DM), and a low-Mg ration high-K (3.88 g Mg/kg DM or 62.1 g K/kg DM). When compared with the low-Mg, low-K ration, the high-Mg, low-K ration raised the absolute apparent Mg absorption (g/day) by 421% and the low-Mg, high-K ration decreased it by 20%. The intake of extra K produced a significant increase in the PDt. The intake of extra Mg did not change the PDt across the rumen wall but produced a significant increase of the ruminal Mg concentrations. On the basis of the individual values for three rations, the mean post feeding ruminal Mg concentrations were found to be unrelated to the PDt (Pearson's r = -0.329, p = 0.183, n = 18). Thus, it is concluded that the observed increase in Mg absorption after a high Mg intake can be explained by an increase in the ruminal Mg concentration rather than by a change in PDt.

Increasing magnesium intakes in relation to magnesium absorption in dry cows.

Earlier studies with temporarily isolated rumen of heifers show saturation kinetics of Mg efflux across the rumen wall. Therefore, we hypothesized that high Mg intakes would not further increase the rate of Mg absorption in cows. To test our hypothesis, six ruminally fistulated non-pregnant dry cows were given diets with different Mg concentrations in a 6 x 6 Latin square design. Desired concentrations of Mg were attained by adding MgO to the basal diet and the Mg concentrations in the total rations were 3.8, 6.4, 9.1, 11.8, 14.1 and 173 g Mg/kg dry matter, which provided Mg intakes of 27.1, 44.6, 64.6, 83.5, 100.4 and 124.3 g/d, respectively. Increasing Mg intakes were associated with increased (P<0.001) faecal Mg excretion. However, apparent Mg absorption expressed as g/d was not significantly different for Mg intakes from 100.4 to 124.3 g/d while Mg absorption expressed as a proportion of intake was not significantly different for Mg intakes ranging from 64.6 to 124.3 g/d. Mg concentrations in rumen fluid after feeding increased (P<0.001) with increasing Mg intakes. Apparent absorption of Mg appeared to become saturated at a ruminal Mg concentration of 17.5 mM (Mg intake of 83.5 g/d). Group-mean post-feeding concentrations of Mg and Na in rumen fluid were significantly correlated (Pearson's r=-0.96; P=0.003, n=6). This study showed that under conditions of practical dairy cow feeding, Mg absorption was maximal at Mg intakes > or = 84 g/d.