Associative effects of supplementing rice straw-based diet with cornstarch on intake, digestion, rumen microbes and growth performance of Huzhou lambs

Review: Composition and utilisation of feed by monogastric animals in the context of circular food production systems

Food production has a major impact on environmental emissions, climate change and land-use. To reduce this impact, the circularity of future food production systems is expected to become increasingly important. In a circular food system, crop land is primarily used for plant-based food production, while low-opportunity cost feed materials (LCF), i.e. crop residues, co-products of the food industry, grass from marginal land and food waste form the basis of future, animal feeds. Animal diets thus contain much less cereals and soybean meal and include a higher proportion of diverse co-products, residues and novel human-inedible ingredients. These diets are characterised by a lower starch content, and a higher content of fibre, protein, fat, and phytate compared to present diets. In this review, possible consequences of the development towards a more circular food system for the type, volume and nutritional characteristics of feed materials and complete feeds are addressed and related research questions in the area of animal nutrition, physiology and metabolism are discussed. Additional attention is given to possible effects on intestinal health and gut functionality and to (bio)technological processing of LCF to improve their suitability for feeding farm animals, with a focus on the effects in pigs and poultry. It is concluded that an increased use of LCF may limit the use of presently used criteria for the efficiency of animal production and nutrient utilisation. Development of characteristics that reflect the efficacy and efficiency of the net contribution of animal production in a circular food system is required. Animal scientists can have an important role in the development of more circular food production systems by focussing on the optimal use of LCF in animal diets for the production of animal-source food, while minimising the use of human-edible food in animal feed.

Effects of supplementation of nonforage fiber source in diets with different starch levels on growth performance, rumen fermentation, nutrient digestion, and microbial flora of Hu lambs

The objectives were to evaluate the effects of fiber source and dietary starch level on growth performance, nutrient digestion, rumen parameters, and rumen bacteria in fattening Hu lambs. A total of 360 Hu lambs (BW = 24.72 ± 0.14 kg, 2 months old) were subjected to a 2 × 3 factorial arrangement. Lambs randomly assigned 6 treatments with 6 repetitions (10 lambs per repetition) of each treatment. Six treatments were formulated to include the fiber sources with three starch levels. The experiment lasted a 63 d. The amount of feed, orts, and total feces were sampled on the 42nd day of the experiment. Rumen fluid samples were collected after 2 h of morning feeding on day 56. Rumen contents were collected last day after the selected lambs were slaughtered. Increasing the starch content decreased the digestibility of neutral detergent fiber (NDF, P = 0.005). Increasing the starch level increased the proportions of propionate (P = 0.002) and valerate (P = 0.001) and decreased the proportion of acetate (P < 0.001) and the ratio of acetate to propionate (P = 0.005). The abundance of Fibrobacter succinogenes was affected by an interaction between the fiber source and the starch level (P < 0.001). Fibrobacter succinogenes tended to be greater in lambs fed SH than in lambs fed BP (P = 0.091), which was greater in lambs fed high starch levels than in lambs fed low starch levels (P = 0.014). Increasing the starch level increased Streptococcus bovis abundance (P = 0.029) and decreased total bacteria (P = 0.025). At the genus level, increasing the starch level reduced the abundance of Butyrivibrio_2 (P = 0.020). Nevertheless, the final body weight (BW) and acid detergent fiber (ADF) digestibility were greater (P < 0.01) in lambs fed soybean hull (SH) than in lambs fed BP. The proportion of butyrate was greater (P = 0.005), while the rumen pH was lower (P = 0.001) in lambs fed beet pulp (BP) than in those fed SH. The abundances of Succiniclasticum, Candidatus_Saccharimonas, Ruminococcus_1, and Christensenellaceae_R-7 were greater in lambs fed SH than in those fed BP (P < 0.050), whereas the abundance of Fibrobacter was lower (P = 0.011). The predominant microbial phyla in all of the groups were Firmicutes, Bacteroidetes, and Fibrobacteres. Changing the starch level for fiber sources mainly changed the rumen community in terms of the phylum and genus abundances. Lambs fed SH with low starch level increased the final BW without affecting total volatile fatty acids (TVFA) concentrations.

Effects of steam-treated rice straw feeding on growth, digestibility, and plasma volatile fatty acids of goats under different housing systems

In order to use rice straw as forage in livestock feeding, the effects of steam-treated rice straw (at 15.5 kgf/cm(2) for 120 s) feeding on growth performance, plasma volatile fatty acid profile, and nutrient digestibility of goats were determined. Twenty male goats (18.69 ± 0.34 kg) were used in an 84-day trial. The goats were divided into four groups of five goats each to receive steam-treated (STRS) or untreated (UTRS) rice straw diet under closed house (CH) and open house (OH) systems. The results revealed that the goats fed with STRS had significantly higher dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility; similarly, the average daily weight gain and feed conversion ratio were higher for STRS groups under both CH and OH systems than those for UTRS. The plasma protein and insulin in STRS and cholesterol in UTRS groups was higher (P < 0.05) at 60 days but found not different (P > 0.05) at 30 days. The plasma amylase, lipase, T3, T4 and glucagon at 30 and 60 days were not different (P > 0.05) among the groups. The plasma acetate, propionate, butyrate, and total volatile fatty acid were higher (P < 0.05) in STRS groups at 30 and 60 days. The housing conditions had no effects (P > 0.05) on these parameters. It could be concluded that steam treatment of rice straw at 15.5 kgf/cm(2) for 120 s increased apparent nutrient digestibility, hence increased the growth and feed efficiency of growing goats.

Influence of varying levels of supplemental cassava root meal without or with groundnut cake on performance of growing Laisind cattle

The objective of this study was to evaluate the effect of supplementation of varying levels of cassava root meal (CRM, 300 and 1,000 g), without or with 700 g groundnut cake (GNC) on intake and performance of growing Laisind cattle fed with a basal diet of urea-treated rice straw (URTRS). Twenty-four male cattle of crossbred Laisind (50% Red Sindhi and 50 % local Yellow, both Bos indicus), from 15 to 17 months of age, 165-175 kg body weight, were used. They were assigned to a completely randomized block design in a 2 × 2 factorial arrangement (two CRM levels and two GNC levels). Intake of URTRS (interaction, P < 0.01) and digestibility of neutral detergent fiber (interaction, P < 0.05) decreased as CRM level increased on the diets without GNC but was not affected by CRM level on the diets with GNC. The total dry matter intake (interaction, P < 0.05) and live weight gain (LWG) (interaction, P < 0.001) increased as CRM level increased on the diets with GNC, but no difference was observed on the diets without GNC. In conclusion, supplementation of 1,000 g CRM should be in combination with 700 g GNC to avoid the negative effects on URTRS intake and digestibility, therefore improving LWG of growing Laisind cattle fed on a URTRS-based diet.

In vitroindications for favourable non-additive effects on ruminal methane mitigation between high-phenolic and high-quality forages

Feeding plants containing elevated levels of polyphenols may reduce ruminal CH4emissions, but at the expense of nutrient utilisation. There might, however, be non-additive effects when combining high-phenolic plants with well-digestible, high-nutrient feeds. To test whether non-additive effects exist, the leaves ofCarica papaya(high in dietary quality, low in polyphenols),Clidemia hirta(high in hydrolysable tannins),Swietenia mahagoni(high in condensed tannins) andEugenia aquea(high in non-tannin phenolics) were tested alone and in all possible mixtures (n15 treatments). An amount of 200 mg DM of samples was incubatedin vitro(24 h; 39oC) with buffered rumen fluid using the Hohenheim gas test apparatus. After the incubation, total gas production, CH4concentration and fermentation profiles were determined. The levels of absolute CH4, and CH4:SCFA and CH4:total gas ratios were lower (P< 0·05) when incubating a combination ofC. papayaand any high-phenolic plants (C. hirta,S. mahagoniandE. aquea) than when incubatingC. papayaalone. Additionally, mixtures resulted in non-additive effects for all CH4-related parameters of the order of 2–15 % deviation from the expected value (P< 0·01). This means that, by combining these plants, CH4in relation to the fermentative capacity was lower than that predicted when assuming the linearity of the effects. Similar non-additive effects of combiningC. papayawith the other plants were found for NH3concentrations but not for SCFA concentrations. In conclusion, using mixtures of high-quality plants and high-phenolic plants could be one approach to CH4mitigation; however, this awaitsin vivoconfirmation.