Dietary Medium-Chain Fatty Acids for Sustainable Ruminant Nutrition

In the current thesis, the potential of krabok oil was investigated to reduce methane production by ruminants. Typically, krabok oil has similar amounts of lauric acid (C12:0) compared to coconut oil but krabok oil also contains ~44% myristic acid (C14:0) and previous research indicated that C14:0 and C12:0 synergistically affected rumen methanogenesis when they were applied as pure fatty acids. In the current thesis it was attempted to assess this synergism in vitro and in vivo, with the use of two natural fatty acid sources, i.e., krabok- and coconut oil. In the first in vitro experiment, rumen methanogenesis and the biohydrogenation of unsaturated long chain fatty acids were assessed. The study consisted of five treatments, The results of this study indicated that both krabok and coconut oil reduced methane production which was coincided with a shift from acetate and butyrate production to propionate. The overall effect of either krabok oil or coconut oil on rumen biohydrogenation was limited. In a subsequent study was conducted to test the defaunating effect of krabok oil in vivo. Three rumen-cannulated beef cows were used to assess the potential of krabok and coconut oil to affect rumen protozoa numbers with experimental treatments arranged in a 3×3 Latin square design. The experimental diets consisted of a concentrate supplemented with either 25.5 g/kg of tallow (control) or the same quantity of coconut oil or krabok oil. Supplemental krabok oil as well as coconut were found to decrease the protozoa numbers, but the effect of coconut oil was more pronounced. The ciliate counts were not significantly different between treatment although the ciliate counts were strongly related to total protozoa counts. Except for propionic acid, the rumen concentrations of the remaining volatile fatty acids were similar between treatments. The two oils did not influence the amylolytic, cellulolytic or proteolytic bacteria counts. Cluster analysis of the denaturing gel electrophoresis profiles of ciliate communities showed a clustering of the coconut oil containing diet and the tallow containing diet. The third study were study in vivo used eight rumen-cannulated bulls, two bulls per treatment. All treatments contained 35 g supplemental fat per kg dry matter: a control diet with tallow; a diet with supplemental coconut oil; and a diet with supplemental krabok oil. The protozoal numbers were reduced by either source of medium chain fatty acids and the strongest reduction was observed when supplemental krabok oil was fed. The abundance of methanogenic Archaea was likewise affected by the experimental diets. The denaturing gradient gel electrophoresis profiles of the rumen archaeal population did not result in a grouping of treatments but in case the diets were supplemented with krabok oil, the richness and evenness were increased within the the archaeal community. The last experiment on vitro was study a dose-response relationship between krabok oil and methane production was also investigated using a fully automated gas production test. The experimental substrates contained either krabok oil (KO), whole krabok seed (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. Both, the absolute (ml/g fat-free OM) and the relative (% of total gas production methane production were reduced at the highest inclusion level of WKS or its derivatives. At the same time, the highest inclusion levels FER, FER+KO, and WKS, but not KO, reduced total gas production and total volatile fatty acids. In current thesis, it was shown that krabok oil is instrumental in mitigating methane emission

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.</p

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

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

In Vitro Rumen Fermentation of Coconut, Sugar Palm, and Durian Peel Silages, Prepared with Selected Additives

Understanding the nutritive values of fruit peel residues could expand our feed atlas in sustaining livestock production systems. This study aimed to investigate the effects of lactic acid bacteria (LAB), cellulase enzyme, molasses, and their combinations on the fermentation quality and in vitro digestibility of coconut peel (CCP), sugar palm peel (SPP), and durian peel (DRP) silage. The CCP, SPP, and DRP were ensiled in a small-scale silo without additive (control), and with LAB strain TH14 (TH14), molasses, or Acremonium cellulase (AC) using a small-scale silage preparation technique according to a completely randomized design. All fresh peels had sufficient factors for ensiling such as moisture content (78–83%), water-soluble carbohydrates (WSC, 4.20–4.61% dry matter (DM)), and epiphytic LAB population (104–105 colony-forming units (cfu)/g fresh matter (FM)). However, aerobic bacteria counts were high (107–109 cfu/g FM). The fiber content of these fruit peels was high, with lignin abundances ranging from 9.1–21.8% DM and crude protein was low (2.7–5.4% DM). After ensiling, the pH values of the silage were optimal (≤4.25) and lower (p < 0.01) for SPP silage. The addition of molasses+TH14, molasses+AC, and molasses+TH14+AC has the potential to enhance fermentation characteristics and improve chemical composition. Silages treated with molasses alone improved the in vitro digestibility of tropical fruit peels. The residue of tropical fruits has the potential to be used as an alternative feed source for ruminants. Adding molasses, TH14, and AC during silage preparation could improve its nutritive value and digestibility