Chromium in the Diet of Dairy Calves: Benefits for Growth Performance, Feed Efficiency, Digestibility, and Health.

Chromium (Cr) is a mineral that helps animals subjected to stressful conditions. The suckling period is characterized by several stressful episodes, particularly during the first hours after birth and at weaning. There is little consumption of concentrate by calves in the first weeks of life; consequently, consuming any supplement added to feed would be negligible. Thus, the hypothesis was that the calves would take it in earlier if Cr were consumed in a milk replacer instead. Therefore, our study aimed to determine whether including organic Cr in calf feed (via milk replacer or concentrate) during the suckling phase would improve calf health and growth performance. Twenty-four male Holstein calves with an average age of 8 ± 4 days and 39.8 ± 6.9 kg average body weight were used. Calves were randomly divided into three groups: (a) Chromium-Milk (CR-M), receiving 4 mg Cr/animal/day via milk replacer during the 60 experimental days of suckling (n = 8); (b) Chromium-Concentrate (CR-C), receiving 4 mg Cr/animal/day via concentrate (n = 8); (c) Control (C), animals that did not receive Chromium (n = 8). The experiment lasted 75 days, divided into two well-defined stages: suckling (1-60 days) and weaning (61-75 days). Body weight weekly, daily feed intake, and blood samples taken every two weeks during the experiment were evaluated. At the end of the experiment, the apparent digestibility evaluation was carried out, with the results of weight and consumption carried out, and a feed efficiency analysis was carried out. It was observed that the inclusion of organic Cr (regardless of whether it was milk or concentrate) increased body weight gain (kg) for the CR-C group: 41.8 kg, CR-M: 40.4 kg compared to the C: 34.2 kg (p = 0.01). The protein digestibility was higher in the CR-M group (52%, p = 0.05). Cr consumption increased Cr concentrations in the serum of the calves and was higher in the first week in the animals in the CR-M group. This did not happen for the C group; however, with higher concentrate consumption, Cr concentrations increased and remained high until the end of the experiment. Glucose concentrations were higher in the groups that consumed Cr. Total protein concentrations were higher in the CR-M and CR-C groups than in group C. Immunoglobulin A concentrations were higher in groups CR-C and CR-M than in group C (days 40 and 60). In conclusion, the adding Cr to calf feed improves their health, indirectly favors growth performance, and increases protein digestibility.

Effect of dietary supplementation with grape residue flour on weight gain, metabolic profile, leukogram, proteinogram and antioxidant response in suckling lambs.

The objective of this study was to determine whether the addition of grape residue flour (GRF) in the diet of suckling lambs would improve their health and consequently enhance their growth. We used 48 lambs, 30 days of age divided into four treatments with four repetitions each, with each repetition consisting of three animals. The groups were identified as follows: G-0%, used as a control (without GRF) and G-0.5%, G-1% and G-2% referring to treatment with grape residue flour in doses of 0.5%, 1%, and 2% of inclusion in the concentrate, respectively. Lambs in groups G-1% and G-2% had higher final body weights, weight gain and average daily gain (ADG) compared to the other groups. GRF dietary supplementation had good antioxidant potential, being able to stimulate glutathione S-transferase (GST) activity and consequently reduce levels of reactive oxygen species (ROS) in lambs that consumed the highest dose of GRF (G-2%). GRF supplementation improved humoral responses, with increased serum levels of heavy-chain and light-chain immunoglobulins; however, there was a reduction in serum ceruloplasmin levels in these lambs. We observed higher concentrations of glucose and triglycerides in lambs in the 2% group. There were lower lymphocyte counts in lambs that received GRF. Lambs supplemented with the highest doses of GRF (G-1% and G-2%) had lower total bacterial counts in the feces. We conclude that the use of GRF in the supplementation of suckling lambs improved animal health, as it stimulated the antioxidant and immune systems and consequently favored their growth.

Positive effects of biocholine powder dietary supplementation on milk production and quality, and antioxidant responses in lactating ewes: A new nutritional tool.

We determined whether the dietary supplementation with a commercial product (vegetable biocholine - VB) for Lacaune ewes at peak lactation would improve animal health and production as well as milk quality. We also determined the effects of VB as a feed additive. We used thirty Lacaune ewes at 30 days of lactation, allocated into three groups: T0 (control, without VB), T5 (5 g of VB/animal/day) and T10 (10 g of VB/animal/day). T10 sheep had greater milk yield during the experimental period. T10 ewes had also a significantly lower feed conversion ratio than the other groups. Total solids concentration of milk was higher in T10 than in the other groups on day 20. The somatic cell count in milk was lower in ewes that consumed VB in the highest dose (T10) than in the T0 and T5 in days 15 and 20. Lower levels of lipoperoxidation (LPO) and of reactive oxygen species (ROS) were observed in milk from ewes fed with the VB supplemented diet on day 20, associated with increased levels of total antioxidant capacity and superoxide dismutase activity in milk. In serum, we found that T5 and T10 animals had significantly higher levels of non-enzymatic antioxidants (non-protein thiols) associated with reduced LPO and ROS content. Higher levels of globulins were observed in T10 than in T0 sheep on day 20. These data suggest that VB dietary supplementation stimulates antioxidant responses and increases the concentration of globulins in a manner beneficial to sheep health. Milk production, feed conversion rate, and milk SCC were also improved.

Effects of biocholine powder supplementation in ewe lambs: Growth, rumen fermentation, antioxidant status, and metabolism.

The objective of this study was to evaluate the effects of biocholine powder (BP) added to the concentrate of ewe lambs on growth, rumen fermentation, antioxidant status, and metabolism. Forty-eight Lacaune lambs were divided 3 treatments: T0, T4, and T8, representing 0, 4, and 8 g of BP per animal/day added to the concentrate, respectively. The T4 and T8 lambs had greater average daily gain from d 0-75 (0.22, 0.25, and 0.26 kg/d for T0, T4 and T8, respectively). T4 and T8 lambs had higher methylene blue test results (indicating microbiological activity), and the higher effects were detected for T8 lambs. The BP in lamb's diet increased the ruminal concentration of propionate (T4 and T8). The T8 lambs had greater serum activity of superoxide dismutase and glutathione transferase, and lower reactive oxygen species levels. We conclude that BP is a biotechnological additive with high nutritional potential.

Lactobacilli Are Prominent Members of the Microbiota Involved in the Ruminal Digestion of Barley and Corn.

The chemical composition of barley grain can vary among barley varieties (Fibar, Xena, McGwire, and Hilose) and result in different digestion efficiencies in the rumen. It is not known if compositional differences in barley can affect the microbiota involved in the ruminal digestion of barley. The objective of this study was to characterize the in situ rumen degradability and microbiota of four barley grain varieties and to compare these to corn. Three ruminally cannulated heifers were fed a low (60% barley silage, 37% barley grain, and 3% supplement) or high grain (37% barley silage, 60% barley grain, and 3% supplement) diet. One set of bags was used to estimate dry matter (DM), starch and crude protein (CP) degradability. A second set was used to extract DNA from the adherent microbiota and visualize grain after incubation using scanning electron microscopy (SEM). DNA was subjected to amplicon 16S rRNA gene sequencing followed by analysis using QIIME. In the low grain diet, McGwire had the highest effective degradability (ED) of DM (P < 0.01). The ED of starch was highest (P < 0.01) for Fibar, McGwire, and Xena, but the ED of CP was not affected by variety. For the high grain diet, Xena and McGwire had the highest ED of DM (P < 0.01). The ED of starch was highest (P < 0.01) for Xena and Fibar. The ED of protein was highest (P < 0.01) for Xena and McGwire. Although the microbiota did not differ among barley varieties, they did differ from corn and with incubation time. Lactobacilli were dominant members of the mature biofilms associated with corn and barley and were accompanied by a notable increase in the lactic acid utilizing genera, Megasphaera. As none of the cattle exhibited subclinical or clinical acidosis during the study, our results suggest that lactobacilli play a more prominent role in routine starch digestion than presently surmised.