Interaction effect of ruminal undegradable protein level and rumen-protected conjugated linoleic acid (CLA) inclusion in the diet of growing goat kids on meat CLA content and quality traits

The Changes in Fecal Bacterial Communities in Goats Offered Rumen-Protected Fat

Leizhou goats are famous for their delicious meat but have inferior growth performance. There is little information on rumen-protected fat (RPF) from the Leizhou goat. Hence, we observed the effects of RPF on growth, fecal short-chain fatty acids, and bacteria community with respect to Leizhou goats. Twelve goats (13.34 ± 0.024 kg) were selected and assigned randomly to one of two treatments: (1) a control diet (CON) and (2) 2.4% RPF with a control diet (RPF). The final body weight and average daily gain (ADG) were greater (p < 0.05), and the dry matter intake (DMI): ADG was lower (p < 0.05) in the RPF group than in the CON group. There were no differences in DMI between the CON and RPF groups. The concentrations of total short-chain fatty acids, acetate, propionate, and butyrate were lower (p < 0.05) in the RPF group than in the CON group. The relative abundances of Ruminococcus, Rikenellaceae_RC9_gut_group, Treponema, norank_f__norank_o__RF39, Eubacterium_siraeum_group, and Ruminococcus_torques_group were lower (p < 0.05) in the RPF group than in the CON group. The relative abundances of Bacteroides, norank_f__norank_o__Clostridia_UCG-014, norank_f__Eubacterium_coprostanoligenes_group, Eubacterium_ruminantium_group, norank_f__Oscillospirale-UCG-010, Oscillospiraceae_UCG-002, and Family_XIII_AD3011_group were greater (p < 0.05) in the RPF group than in the CON group. It was concluded that RPF could improve the goats' growth performance by regulating their fecal bacteria communities.

Effects of Soybean and Linseed Oils Calcium Salts and Starter Protein Content on Growth Performance, Immune Response, and Nitrogen Utilization Efficiency in Holstein Dairy Calves

This study aimed to investigate the interaction of fatty acid (FA) source [calcium salt of soybean oil (n-6 FA) vs. calcium salt of linseed oil (n-3 FA) both 3% DM basis] with protein content (18% vs. 22% CP, based on DM) on growth performance, blood metabolites, immune function, skeletal growth indices, urinary purine derivatives (PD), and microbial protein synthesis (MPS) in young dairy calves. Forty 3-day-old calves (20 females and 20 males) with a starting body weight (BW) of 40.2 kg were assigned in a completely randomized block design in a 2 × 2 factorial arrangement of treatments. Experimental diets were: (1) n-6 FA with 18% CP (n-6-18CP), (2) n-6 FA with 22% CP (n-6-22CP), (3) n-3 FA with 18% CP (n-3-18CP), and (4) n-3 FA with 22% CP (n-3-22CP). Starter feed intake and average daily gain (ADG) were not influenced by experimental diets (p > 0.05). However, before weaning and the entire period, feed efficiency (FE) was greater in calves fed n-3 FA compared to n-6 FA (p < 0.05). Heart girth (weaning, p < 0.05) and hip height (weaning, p < 0.05 and final, p < 0.01) were highest among experimental treatments in calves who received n-3-22CP diets. The greatest blood glucose (p < 0.05) and insulin (p < 0.01) concentrations in the pre-weaning period and the lowest serum concentration of tumor necrosis factor (before weaning, p < 0.05) were observed in calves fed the n-3-22CP diet. However, the greatest blood urea N (before weaning, p < 0.05; after weaning, p < 0.05) and urinary N excretion (p < 0.05) were found in calves fed n-6-22CP diets compared to other experimental arrangements. In conclusion, offering calves with Ca-salt of n-3 FA along with 22% CP content may be related to improved nitrogen efficiency and immune function.

Supplementation of n-3 fatty acid and ruminal undegradable to degradable protein ratio in young lambs raised under heat condition: effects on growth performance and urinary purine derivatives

The present study evaluated the effect of supplementation alpha-linolenic fatty acid source (ALA) with different rumen undegradable to degradable protein ratios [low ratio (LR) = 26:74; high ratio (HR) = 36:64 based on CP%] on growth performance, nutrient digestibility, fecal score, animal feeding behavior, and urinary purine derivatives (PD) in young lambs during hot season. Forty 10-day-old lambs (averaging body weight of 7.9 ± 0.8 kg) were used in a completely randomized block design with a 2 × 2 factorial arrangement as following treatments (10 lambs/treatment): (1) no n-3 FA supplementation with LR diet (NALA-LR), (2) no ALA supplementation with HR diet (NALA-HR), (3) supplementation of ALA with LR diet (ALA-LR), and (4) supplementation of ALA with HR diet (ALA-HR). Results showed that ALA supplementation slightly increased feed efficiency (FE; tendency, P = 0.076), improved fecal score (P = 0.045), and reduced rectal temperature (tendency, P = 0.064) during pre-weaning period. The HR diets improved average daily gain (ADG; P < 0.01), wither height (post-weaning; P = 0.015), and final BW (P = 0.048) compared with LR diets. The greatest ADG (pre-weaning; P = 0.012), structural growth, and the lowest urinary nitrogen exertion (P = 0.043) were found in the ALA-HR treatment. No change was found for ruminal fermentation, nutrient digestibility, and animal behavior in lambs fed different experimental treatments. In summary, results indicated that concurrent feeding of ALA and high dietary RUP:RDP ratio can be recommendable that is likely due to more efficient nitrogen utilization when young lambs are raised during hot season. HIGHLIGHTS: • The interaction of n-3 FA and nitrogen was evaluated in pre-weaning lambs raised under heat condition. • Supplementation of n-3 FA increased FE and improved fecal score in heat-exposed lambs during pre-weaning period. • The high RUP:RDP ratio improved skeletal growth during post-weaning period. • Concurrent feeding of n-3 FA and high dietary RUP:RDP ratio is recommendable in young lambs raised during hot season.

Effects of Diets Containing Finger Millet Straw and Corn Straw on Growth Performance, Plasma Metabolites, Immune Capacity, and Carcass Traits in Fattening Lambs

As the byproduct of finger millet, millet straw is a new forage resource of ruminants. The effect of the combined utilization of millet straw with corn straw on fattening lamb production is seldom reported. The purpose of this study was to investigate the effect of different proportions of millet straw instead of corn straw on the growth performance, blood metabolites, immune response, meat yield, and quality of fattening lamb. Sixty-three-month-old healthy Small-Tailed Han sheep crossbred rams with an average initial weight of 19.28 ± 2.95 kg were randomly divided into four groups, with three replicates in each group and five lambs in each replicate. The replacement ratio of millet straw of each group (Group I, II, III, IV) was 0%, 25%, 35%, 50% at the first stage (the first two months) and 0%, 20%, 28%, 40% in the second period (final two months), respectively. The experiment lasted 4 months 10 days of the pre-feeding period. The results indicated that the body weight gain and average daily gain of group Ⅱ were significantly higher than those of group Ⅰ and group Ⅳ (p < 0.05). The concentration of total protein in group Ⅳ was significantly increased compared to those of the other three groups at the second stage (p < 0.05), which proved that the protein synthesis metabolism capacity was improved with the addition of millet straw. The concentration of the plasma glutamic-oxalacetic transaminase and lactic dehydrogenase of lambs was significantly decreased in group Ⅱ (p < 0.05). The combination of millet straw and corn straw had no impact on the glucose, total cholesterol, and triglycerides metabolism (p > 0.05). There was no significant difference in the pre-slaughter weight, carcass weight, dressing percentage, loin-eye area, and GR value among the four groups (p > 0.05). Furthermore, the immune response and meat quality were not impacted by the different proportions of millet and corn forage diets. The results showed that the combined utilization of millet straw with corn straw could improve the blood biochemistry metabolism capability of fattening lambs. The replacement of 50% of corn straw with millet straw could improve the growth performance and be an application in fattening lamb production.