Effect of replacing cottonseed meal with canola meal on growth performance, blood metabolites, thyroid function, and ruminal parameters of growing lambs

The objective was to clarify the impact of replacing cottonseed meal with canola meal (CM) on growth performance, blood metabolites, thyroxin function, and ruminal parameters of growing lambs. Twenty-four growing Barki male lambs (4-5 months of age) were assigned randomly into four equal groups (6 lambs each). Four dietary treatments were the control group with 0% CM (CON) and three experimental groups where CM replaced 25% (CN₁), 50% (CN₂), and 75% (CN₃) of cottonseed meal. There were no dietary effects (P > 0.05) on the lambs' feed intake, average daily gain, and feed conversion ratio of the lambs. The dietary CM linearly decreased the concentrations of serum total proteins (P = 0.003), albumin (P = 0.010), globulin (P = 0.011), AST (P = 0.041), and urea (P = 0.001) in growing lambs. The levels of ALT and creatinine, however, were not significantly affected by dietary treatments (P > 0.05). Furthermore, serum triiodothyronine, thyroxine, and electrolyte concentrations were similar (P > 0.05) in different dietary groups. Dietary treatments significantly affected the values of ruminal pH and ammonia at 0 h (P = 0.003 and 0.048, respectively) and 3 h (P = 0.033 and P = 0.006, respectively) postfeeding. The CN₃ group showed significantly higher concentrations of ruminal ammonia at 0 and 3 h postfeeding. Furthermore, dietary CM (CN₃) significantly reduced the ruminal pH values at 0 and 3 h postfeeding. Meanwhile, dietary treatments did not affect the concentration of total VFAs in the ruminal fluid. In conclusion, CM can replace the cottonseed meal (up to 75%) in lamb diets without compromising their growth performance, thyroid function, and ruminal fermentation parameters.

In Vitro Screening of East Asian Plant Extracts for Potential Use in Reducing Ruminal Methane Production

Indiscriminate use of antibiotics can result in antibiotic residues in animal products; thus, plant compounds may be better alternative sources for mitigating methane (CH₄) production. An in vitro screening experiment was conducted to evaluate the potential application of 152 dry methanolic or ethanolic extracts from 137 plant species distributed in East Asian countries as anti-methanogenic additives in ruminant feed. The experimental material consisted of 200 mg total mixed ration, 20 mg plant extract, and 30 mL diluted ruminal fluid-buffer mixture in 60 mL serum bottles that were sealed with rubber stoppers and incubated at 39 °C for 24 h. Among the tested extracts, eight extracts decreased CH₄ production by >20%, compared to the corresponding controls: stems of Vitex negundo var. incisa, stems of Amelanchier asiatica, fruit of Reynoutria sachalinensis, seeds of Tribulus terrestris, seeds of Pharbitis nil, leaves of Alnus japonica, stem and bark of Carpinus tschonoskii, and stems of Acer truncatum. A confirmation assay of the eight plant extracts at a dosage of 10 mg with four replications repeated on 3 different days revealed that the extracts decreased CH₄ concentration in the total gas (7-15%) and total CH₄ production (17-37%), compared to the control. This is the first report to identify the anti-methanogenic activities of eight potential plant extracts. All extracts decreased ammonia (NH₃-N) concentrations. Negative effects on total gas and volatile fatty acid (VFA) production were also noted for all extracts that were rich in hydrolysable tannins and total saponins or fatty acids. The underlying modes of action differed among plants: extracts from P. nil, V. negundo var. incisa, A. asiatica, and R. sachalinensis resulted in a decrease in total methanogen or the protozoan population (p < 0.05) but extracts from other plants did not. Furthermore, extracts from P. nil decreased the population of total protozoa and increased the proportion of propionate among VFAs (p < 0.05). Identifying bioactive compounds in seeds of P. nil by gas chromatography-mass spectrometry analysis revealed enrichment of linoleic acid (18:2). Overall, seeds of P. nil could be a possible alternative to ionophores or oil seeds to mitigate ruminal CH₄ production.

Can we improve the nutritional quality of meat?

The nutritional value of meat is an increasingly important factor influencing consumer preferences for poultry, red meat and processed meat products. Intramuscular fat content and composition, in addition to high quality protein, trace minerals and vitamins are important determinants of nutritional value. Fat content of meat at retail has decreased substantially over the past 40 years through advances in animal genetics, nutrition and management and changes in processing techniques. Evidence of the association between diet and the incidence of human non-communicable diseases has driven an interest in developing production systems for lowering total SFA and trans fatty acid (TFA) content and enrichment of n-3 PUFA concentrations in meat and meat products. Typically, poultry and pork has a lower fat content, containing higher PUFA and lower TFA concentrations than lamb or beef. Animal genetics, nutrition and maturity, coupled with their rumen microbiome, are the main factors influencing tissue lipid content and relative proportions of SFA, MUFA and PUFA. Altering the fatty acid (FA) profile of lamb and beef is determined to a large extent by extensive plant and microbial lipolysis and subsequent microbial biohydrogenation of dietary lipid in the rumen, and one of the major reasons explaining the differences in lipid composition of meat from monogastrics and ruminants. Nutritional strategies can be used to align the fat content and FA composition of poultry, pork, lamb and beef with Public Health Guidelines for lowering the social and economic burden of chronic disease.

Addition of an extract of lucerne (Medicago sativa L.) to cattle diets - Effects on fatty acid profile, meat quality and eating quality of the M. longissimus muscle

There is considerable interest in enhancing beneficial fatty acids, particularly 18:3n-3, conjugated linoleic acid and long chain n-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in beef to provide benefits to human health. Here, the potential to enhance these fatty acids by feeding a n-3 polyunsaturated fatty acid (PUFA)-rich plant extract (PX) from lucerne is presented. Cattle (n=8/diet) were assigned to the following finishing diets: straw and concentrate (S-CC); straw and concentrate containing 25% PX and 2000IUvitaminE/kg PX-concentrate (S-PXC); grass silage (GS); GS plus 75gPX/kg dry matter intake (DMI) (GS-LPX) or GS plus 150g PX/kg DMI (GS-HPX). Addition of PX to concentrates or GS increased the n-3 fatty acid content of loin muscle and had favourable effects on the n-6:n-3 PUFA ratio (P<0.05), without detrimental effects on loin muscle sensory characteristics.